Linux users: Install iPodLinux on your iPod without losing any of your existing content with a script introduced by Mike's Ubuntu Blog. The script automatically partitions your iPod's hard drive and installs a boot partitioner with just three terminal commands.
wget http://de.dataghost.com/ipl/dg-installer/dg-linux-installer-20070311.tar.bz2
tar -jxf dg-linux-installer-20070311.tar.bz2
sudo ./installer.sh
I installed iPodLinux on my iPod, and besides an occasional freeze up (and a decent drain on the battery), iPodLinux has been running very well. After installing iPodLinux you'll still be able to sync your iPod just as you normally would in addition to doing other fun things, like playing games. If you're not running Linux, you can still install iPodLinux on your iPod from your Windows or Mac PC.
How to: install ipodlinux on your ipod [Mike's Ubuntu Blog]