I might have to get over my current dislike of Jim Carrey for this one.

From MovieWeb.com:

Carol Burnett, Will Arnett, Seth Rogan, Isla Fisher, Dan Fogler, Amy Poehler, Dane Cook, Jaime Pressly and Jonah Hill are all lending their voices for the cast of the CG-animated comedy, Horton Hears a Who for 20th Century Fox Animation and Blue Sky Studios.

Jim Carrey will play Horton and Steve Carell will play the Mayor of Who-ville in the adaptation of the Dr. Seuss book; according to Variety, Burnett will voice the role of the always skeptical Kangaroo, however, no other characters were announced.

Will Arnett*, Amy Poehler, Steve Carell AND Seth Rogan?  I'm there. 

It'll be possible to just ignore Horton, right?  I mean, I just watched Four Weddings and a Funeral last night, and discovered that if you ignore everything Andie McDowell does or says, it really is a decent movie.  Kind of how Twin Peaks is so much better if you fast-forward through all of the Donna scenes.  Especially the ones with lame-o Harold.

*S.W.O.O.N.