Is there a way to convert music files that are in my WMP library?

I ripped my entire music collection onto WMP thinking I would be able to put them on my PSP but nooo it's in the wrong format. Here's the kicker, I could have ripped them into MP3 format, but I didn't. Anyway I don't want to re-rip every single CD so what's the fasted method of converting my music (and having them in my WMP library)?