The encoders were removed from ffdshow due to being "outdated and buggy". Very, very sad thing to do :(
If you want to use the encoders, you should install a version which still has them, latest being from somewhere around Dec/2010. More info from doom9's forum or from the home page,
@K D DOGG & @gamerfreak & others who are concerned:
The developers of ffdshow have decided (at least until there are enough people asking for them) to drop the encoders out of the program. Reasons are (quoting from memory here, NOT verbatim) that the code is "buggy, outdated, obsolete and difficult & time-consuming to update", and that there are better, stand-alone products to replace them.
But it seems if enough people start to make noise about the missing encoders, there might still be hope for them to be re-integrated; go to the doom9's forum and read the discussion, and if You feel like it, post your opinions eg. somewhere here: http://forum.doom9 .org/showthread.php?p=1463368#post1463368
Otherwise 5 star product, but the missing encoders drop half of the use cases :(