Previously I mentioned about FairUse4WM which allows you to remove the DRM license from Microsoft’s PlayForSure WMA music files. Now there’s a new free 50 KB utility to remove the iTunes DRM license from AAC files called Mytunes (via Engadget).
But this software isn’t simple as FairUse4WM. You have to play all iTunes songs that you want to strip and this utility will strip the DRM from the AAC files in the background to a folder that you select. After which you need to convert the stripped files back to the AAC format.

Here’s how to use the software (from the Hymn forum)

1) Run iTunes 6.0.5.x
2) Run myTunes
3) Click “Enable myTunes”
4) Start Playing Audio Files, They will be dumped to the folder you selected.
5) Click “Disable myTunes” to stop (might have to click in itunes after stop)

To convert AAC Stream to playable AAC file, use FAAD like so:
faad.exe -a myFilexx.aac myTunesxx.aac

Download link for Mytunes- http://rapidshare.de/files/31538931/myTunes.rar.html

See also- Fairgame-Remove Apple iTunes 7 AAC DRM protection on Mac OS X 10