FYI: iTunes 10 - now exports playlists from iPod
as .txt, .xml, .m3u, .m3u8 and unicode.
Note that this does not export the songs, just a playlist with the song info. So if you lose the playlist in iTunes and it's on the ipod simple enough to recover.
Mac mini (mid 2010) - 2 GB RAM, Mac OS X (10.6.4), silver mini, blue mini, silver shuffle, iTunes 9.1.1 (12)