Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_2 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5G77 Safari/525.20)
If you're talking about ripping DVDs for the iPod Touch, I use HandBrake. The presets are really nice. I think that you may be able to convert files that are already on your computer. I've never tried the second option though.