FairUse4WM has been fairly well known for its ability to the Windows Media DRM and with its latest version 1.3 it boasts to be able to completely remove the digital rights management restrictions from songs purchased from the Zune Marketplace; a feat to which it was previously unsuccessful.
This, like most of these situations, will likely be short lived. Microsoft is undoubtedly already well on there way with a new version of software for the Zune to combat the latest FairUse4WM version. But, until then you can use this to release your songs from the DRM clutches. If you’re too late for this version you’ll likely get another chance, that is until Microsoft figures out who the heck “viodentia”, (the FairUse4WM author) is.