Capcom has gone about updating their Marvel vs. Capcom 3 website with the most recent additions to the line-up. Look at their site, there are only two blank spots remaining for the game.
The roster so far (thanks to VG247):
Marvel
* Captain America
* Deadpool
* Doctor Doom
* Dormammu
* Hulk
* Iron Man
* Spider-Man
* Super-Skrull
* Thor
* X-23
* Wolverine
Capcom
* Amaterasu
* Chris Redfield
* Chun-Li
* Dante
* Felicia
* Morrigan
* Ryu
* Trish
* Tron Bonne
* Viewtiful Joe
* Wesker
The game is slated for a Spring 2011 release.
We've got the full list of Marvel vs. Capcom 2 achievements - check the list for guides to unlocking them.