Sure. Dish has announced a special channel for the Olympics which I think they are broadcasting on the PPV channel (9467). That one is MPEG-2 and all subs with HD receivers will get it.
Also, I could be wrong, but I think that NBC will have quite a bit of their coverage in HD. So there are two channels right there that will show you about as much as HD coverage you will need to see of the Olympics.
The only channel you won't have is UniversalHD because that is MPEG-4, but I have heard that they just mirror content of MSNBC Olympic coverage (SD) so it's not like you will miss anything as long as you have MSNBC.
If anyone wants to correct me on some of this, please chime in! But this is what I understand is happening up to this point. I am a huge hockey fan so it matters to me too. (622 will be installed on 2/22).