It's been out for a few hours now, and we've all had our chance to give it a quick once over. Fr. Z was lucky enough to be able to prepare his analysis in advance, so my remarks are necessarily going to be somewhat similar to his. I'm going to start at the beginning and address anything of interest that I see as we move along. I'm glad it's a short document; otherwise I wouldn't be able to finish the whole thing in time.
First of all, we see the use of my favourite phrase: Lex orandi, lex credendi. Never a bad thing to see that. The document refers to the very obvious fact that our sacramental practices must be maintained for the sake of the entire Church.
After that we see a very brief history of the old Mass since Vatican II. Bl. John Paul II granted an indult (Quattuor abhinc annos), followed by a motu proprio (Ecclesia Dei) which allowed the TLM to be said with permission from the ordinary, which was to be generously granted.
Next , §7, we find an explanation of why the TLM seemed to be effectively forbidden after Vatican II, even though Summorum Pontificum states that it was never abrogated. "Such norms needed on account of the fact that, when the new Missal had been introduced under Pope Paul VI, it had not seemed necessary to issue guidelines regulating the use of the 1962 Liturgy." This may be a little bit of whitewashing; from what I hear, the TLM was effectively forbidden for many of those years. However, since I didn't experience it myself, I'm willing to accept it.
I think that the last paragraph of §7 is especially important. "What was sacred for prior generations, remains sacred and great for us as well, and cannot be suddenly prohibited altogether or even judged harmful." This was quoting Pope Benedict in 2007. In my opinion this puts into their place those opinions that we are Latin Catholics are obliged to attend to Ordinary Form simple because it is Ordinary. I consider this opinion to be incorrect and harmful to those who are attached to the old Mass, or those who may in the future wish to know more about it. In fact, I think it can be argued based on these passages that, for those who are attached to the TLM, it is in fact a responsibility to attend. As we see in §8, the old Mass is "considered as a precious treasure to be preserved." Who is to preserve it but the priests and laypeople? It is not merely our right to attend Mass in this form, it is indeed our responsibility to see it made available as widely as possible.
The Responsibilities of the Pontifical Commission Ecclesia Dei:
This section is quick and interesting in that it specifically places the authority of Ecclesia Dei above the local ordinary in matters regarding the TLM. We've been given recourse the Ecclesia Dei then, if our bishops are resistant to introducing the Extraordinary Form. I'm thinking at the moment of the time a couple hears ago (during the H1N1 scare) where my bishop temporarily suspended Communion on the tongue. The FSSP politely (and quite rightly) indicated that they could not comply with this directive (they cannot still, according to a section later on in this document), so the TLM was suspended until that directive was lifted. I don't think this was appropriate on the part of my bishop, and now if something similar happens in the future, Ecclesia Dei has the authority to override him.
In §15 we see first a bit of directive as to what defines a "coetus fidelium", the group of the faithful mentioned in Summorum Pontificum. First, there is again no mention of numbers. As far as I'm concerned a group consists of three or more, and I believe that since both Summorum Pontificum and Universae Ecclesiae decline to go into any detail, we are to assume that a small group carries just as much weight as a large one. In fact, according to §17.2, if a group is very small they are to approach the Ordinary (bishop), who is to make the Mass available for them at a particular church. Also, this group need not be composed solely of members of that particular parish.
As per §16, if a group of the faithful has a priest who is willing to say the TLM for them, and this priest presents himself at a parish or oratory, he is to be given that opportunity by the pastor (within the reasonable bounds of the parish's regular schedule).
The only stipulation on groups of the faithful is that they may not "support or belong to groups which show themselves to be against the validity or legitimacy of the Holy Mass or [...] against the Roman Pontiff as Supreme Pastor of the Church." Not even those people who attend SSPX Masses can be said to belong to this. I don't even know why a group of sedevacantists/sedeprivationists, etc., would want to celebrate Mass within the Church, but there you go.
With regards for qualified priests, we see that a priest is considered qualified to say Mass in the Extraordinary Form if he is not impeded by canon law, has a basic knowledge of Latin so as to pronounce the words and understand their meaning, and have celebrated it in the past.
Furthermore (§21), we see that seminarians are to be given the opportunity to learn the Extraordinary Form, and we are also reminded of the obligation to be familiar with Latin. Sadly the knowledge of Latin is not currently a part of most seminary curricula, and I'm not sure what we can do right now to change that.
According to §24, the rubrics of the 1962 missal must be followed when celebrating that Mass. I figured this was self-evident, but just recently we heard about a parish in which the TLM was celebrated with female altar servers. Thankfully this is clearly not permitted in the TLM. This would also reaffirm the position of the FSSP with regards to the H1N1 issue I mentioned above.
However (and this was also self-evident, in my opinion), regarding the disciplinary norms connected to celebration, the 1983 Code of Canon Law is to be observed. If I'm not mistaken this includes such things as the Eucharistic fast, the number of times a person can participate in Mass in a single day, the wearing of veils etc..
According to §31, only Institutes of Consecrated Life and Societies of Apostolic Life are permitted to ordain (minor or major) in the older form of the Mass. This was the case before, so nothing new here, although I have to admit that I don't understand the reasoning behind this. Would be nice if it changed sometime in the future.
With regards to the Easter Triduum, it is the right of the faithful to celebrate in the Extraordinary Form (§33), and if there is no church exclusively for their use, they are to be accomodated, "not excluding the possibility of a repetition of the celebration of the Sacred Triduum in the same church." This is what happened in my diocese, since the FSSP share a diocesan church.
So, that's how it is. It's a very good document, and it gives us a bit more legal weight when asking that the TLM be celebrated regularly. It's important to note, like I said above, that not only is it our right to participate in the Extraordinary Form, it is in fact our responsibility to see that it is faithfully maintained. I think we should be proud of this responsibility. We are going to contribute to the liturgical renewal of the Church, and participating in the Traditional Mass is a perfectly legitimate means of doing so. Also important to remember is that Ecclesia Dei has immediate authority with regards to the old Form over our local bishops, so if they for any reason resist regular implementation of the TLM, we have an advocate in Ecclesia Dei.
We should thank Ecclesia Dei and the Holy Father for this Instruction, and as always we should pray that the TLM is made widely and regularly available across the entire world, for the sanctification of us and our brothers and sisters in the faith.