There's no such thing as an "ipod" music format. iPods play music in either mp3 or aac/mp4 formats (as well as
a few others), with the aac files optionally including apple DRM protection.
For unprotected mp3 and aac files, just about any media player can handle them, as long as you have proper codec support for those formats installed. Note that, since these formats are patent-encumbered, most distros are unable to provide them automatically, but you're free to install them manually. A simple google search should give you pages on how to set up support for them.
Nothing legal is going to be able to give you playback on DRM-encumbered files. But there may be ways to strip the DRM or convert them to other formats. At the very least, the "burn to CD" with itunes on Windows, followed by re-ripping to another format, generally works.