Oh, wow, now this is good news: the iPod Touch now works properly with Ubuntu 10.04, specifically, with Rhythmbox. Plug in the iPod Touch and Ubuntu offers to start up the app. You can drag and drop MP3 files into the iPod Touch.
The Rhythmbox that came with older versions of Ubuntu didn't properly recognize the iPod Touch (though older iPod players worked fine.) I gave up trying to get them to work as all I really used the iPod Touch for was as web browser and e-book reader. iTunes was just too much of a hassle to work with.
Now that things just work, I expect to be using the iPod Touch more.
Presumably this works for the iPhone as well, but I don't have one to test with.