Mpeg4!! No mpeg1…its ooollddd…lol Anywayz…
To answer your question, get adobe premiere. Its the best for doing all video editing (that I’ve used…I have yet to get my hands on avid or final cut pro 
) It lets you export to whatever format you want.
I’d also like to take this oppurtunity to remphaize (I can’t spell…) rendering to TARGAs. Targas are awesome for everything, for showing off and for having some nice uncompressed video or stills. Any questions IM me @ specialagentjim
and im off!