I stumbled into this nice little FREE video mp4 (and other formats) to 3gp converter to view on your cellphone or other supporting devices. On my windows box (3Ghz) a full length movie from my OSD takes about 15 minutes to convert to 3gp.
ABC 3GP/MP4 Converter is software for 3GP/3GP2/MP4 file conversion of portable device. It can convert almost all video formats, for e.g., DivX, XviD, MOV, rm, rmvb, mkv, MPEG, VOB, DVD, WMV, AVI, AVS, ASF, H264, to 3GP/3GPP2/MP4 format for playing on mobile phone such as Nokia, Sony Ericsson, Motorola or PSP, iPhone, iPod and other portable video device. It integrated H263 codec which has super fast conversion speed with high quality. And it supports merge many video clip into one. It also has the option to preview the video in real-time. With skinable, easy to use user interface, you can do your job very easily.
http://www.freedownloadmanager.org/downloads/ABC_3GP_MP4_Converter_52522_p/
