What are you using to convert DRM WMA files?

I am generally annoyed right now... My local library offers audiobook downloads but they come in MS WMA format with DRM that I can't play on my ipod. I assume that I can play them on my psp with WMA playback but it is clunky to carry it around while I am working so my nano is much more useful. I have seen a lot of software that costs money but is there a free option that anyone is using? I would just copy to disk and rip back to mp3 but an audiobook usually requires ~10-15 disks. Any help will be appreciated.
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