I would like a 3gp video, with less quality, so it will be smaller 
What phone will you be using?
(I'm asking this of everyone because different phones have different allowances for codecs and features of said codecs - MP4 and 3GP are just containers, they could have any number of possible codecs inside them (AVC, Xvid, DivX, MPEG-4 SP, etc...))
As for the Nokias, the only way i could find so far is by using QuickTime *shudder*
I really don't want to use said crapware on my PC, so if anyone has a copy of QuickTime
Pro, let me know, much thanks, I'll send you a guide on how to convert these videos.
Otherwise please be patient, I'll try a few profiles myself in x264...
Oh, and smaller than the 12MB MaSu's official 3GP is at? That's gonna suck :lol: