iTunes 8 DRM Removal Question: Remove DRM from huge library of music and videos (PC)

What is the best and most efficient way to remove the DRM on songs downloaded using iTunes 8. My issue is this...I have some of my friend's music and videos that he purchased from the ITunes store and he wants me to de-authorize my computer. This would effectively leave me with tons of useless files on my computer. Would removing the DRM help me here? If so I would remove the DRM then depermission my computer.

I know you can burn the songs to a cd and then copy them back but I have many gigs worth of music that I want to do this for. Is there a software package that will quickly remove the DRM for my entire library, for music and video?

FYI, I have a PC.

THANKS!!!!!