Is not cool to only be able to browse movies and not been able to see them unless they are mpeg4 on the ps3… so a fast and easy way to convert them is this:

First install GPAC
(GPAC is an implementation of the MPEG-4 Systems standard developed from scratch in ANSI C)

using gentoo:
emerge media-video/gpac
if using other system:
apt-get install gpac or just get it from the home page here

I found this lite batch script the other day on the ps3forums:

#!/bin/sh
##Released under the GPL.
## www.subvida.com
## Carlos Rivero
function usage {
cat eof $0 inputFile outputFile bitrate
where
    inputFile: The video to convert
    outoutFile: The output video
    bitrate: bitrate for the output (ex: 2000)
EOF
exit 1
}
[ $# -lt 3 ] && usage

echo "EXECUTING COMMAND: mencoder $1 -ovc x264 -oac faac -x264encopts subq=6:pass=1:bitrate=$3:bframes=3:partitions=p8x8,b8x8,i4x4:weight_b:threads=auto:nopsnr:nossim:frameref=3:mixed_refs:bime:brdo:level_idc=41:direct_pred=auto:trellis=1 -o "$2.avi""
echo "Now converting to AVC.  This will take the most time." + `date`

mencoder $1 -ovc x264 -oac faac -x264encopts subq=6:pass=1:bitrate=$3:bframes=3:partitions=p8x8,b8x8,i4x4:weight_b:threads=auto:nopsnr:nossim:frameref=3:mixed_refs:bime:brdo:level_idc=41:direct_pred=auto:trellis=1 -o "$2.avi"

echo "Now converting avi to MP4, due to limitations."
MP4Box -aviraw video $2.avi
MP4Box -aviraw audio $2.avi
mv $2_audio.raw $2_audio.aac
MP4Box -add $2_audio.aac -add $2_video.h264 $2.mp4

which should be run like: bashscript INPUT.avi OUTPUT bitrate

use this script in conjunction with this

*NOTE: replace line 6
cat eof $0 inputFile outputFile bitrate
by
cat <<eof $0 inputFile outputFile bitrate