PSP MP4 Converter

..anyone can suggest me some good freeware converter from most common used video formats in to MP4...I would like to convert some movies for my PSP..

I use the following for all my psp video needs:
http://www.pspvideo9.com/

It is free as well :)

I use this for my PS3 vids, it also does them for PSP, DS, and loads more too.
http://www.redkawa.com/videoconverters/ps3video9/