MacRumors.com

An application called Playfair has been released.

This application takes protected AACs from the iTunes Music Store and decrypts them into unprotected AACs. From the site:

It takes one of the iTMS Protected AAC Audio Files, decodes it using a key obtained from your iPod or Microsoft Windows system and then writes the new, decoded version to disk as a regular AAC Audio File. It then optionally copies the metadata tags that describe the song, including the cover art, to the new file.

According to reader feedback, the application does work as described, allowing owners of purchased songs to convert their Protected AACs into UnProtected AACs. Due to the key-based system, users are not able to decode protected AACs from other individuals (only ones they own).

The application is presently only available as source code and requires compilation.

At least one previous application (QTFairUse) attempted to circumvent Apple's iTunes digital rights management.