Non of them are specific to one for the resolution I mention, most seem to be for different ones. As you know, each phone is different and therefore has different requirements. I did follow one of the guides for the E61 (i think) and the quality was good but didn't have the widescreen black bars top and bottom on.
I'm using Super and DivX Player. The best combination I've foud is around 300kbps for a 320x240 video and 96kbps for stereo sound. The video/sound sync is not perfect, but is the best free option at this moment. Mp4 files are big and they do not offer the same video quality at the same bit rate.
Been playing around with various progs and various settings for most of the week. I reckon I've come up with some bloody good settings for the E60 and it can be easily adapted to accommodate other resolutions.
encode video with PocketDivXEncoder using the iRiverPMP100 as the device and using Maximum dimentions below that. Also had 'two pass encoding' and 'audio normalisation' ticked. Open your video and change the output setting to 416 (E60) x (whatever it goes to) then ok this. I altered the video quality setting to 16 (bitrate 304) and audio to 7.
I've been using smartmovie to watch the finished product full screen.