Can't she just copy the songs back using iTunes itself as long as it's on the same machine that put the songs onto the iPod? Of course I won't be surprised if you can't.

Other than that there are plugins for Winamp, Songbird as Matt suggested, Xpod, Anapod, and probably at least half a dozen more. For Windows and Mac OS.

Senuti for Mac OS works as advertised with an iPod Touch. You may need to use WinAmp with a plugin for the Touch under Windows.