iTunes does not like m3u files. Or at least not the kind that ampache spits out. For the uninitiated, here's the flow of things to get music streaming to your computer:
1. Find friend with *humungous* music collection.
2. Get said friend to give you access to his collection.
3. Friend runs ampache which looks so ugly that you can't wait to get off the webpage and onto the listening. But that's okay, because the music is really good, and there are few other solutions out there that do *exactly* what you want, despite really bad html+css (user xp? what's that?)
4. Get the m3u playlist you want to play.
5. Watch iTunes add *each* song into its library as if it were a different song.
[scream in frustration]
6. Google search like crazy. Not compromising on:
6a. ampache, or
7. Turns out I'm not the first to notice iTunes's brokenness and people with more time than me have created a nifty utility called m3u2itunes which sort of fixes the problem. In the same way that a spare tire solves a flat tire problem. Which is to say, it doesn't solve it at all, but at least makes the experience a little less like a dentist appointment.
8. Be happy again. You can listen to said friend's library *and* not destroy your itunes catalog in the process. Woot.