Compressor is Mac only and comes bundled with Final Cut. Sorensen is Mac and PC, quite expensive for a stand-alone and I everybody I know using this purchased it bundled with Avid’s Media Composer. You may also try Quicktime Pro, has a lot less features than the above mentioned but is only 29$.
Super © is freeware, I remember a sticky either in the comp/editing or After Effetcs Forum with a few more links and a short encoding guide.
You may also render uncompressed and then encode that uncompressed output in After Effects. I do know that it’s not recommended, but it’s better than nothing. Settings can be adjusted in the render output menu in the render list(reading the manual helps).