You can check on iTunes to see if any of your purchased music can be upgraded to iTunes+. I think it's 30 cents per song (don't know the per album charge). iTunes+ gives you a new copy of the song at a higher bit rate and with the DRM protection removed.
funny thing, i burned a cd of my purchased music, then went to put the mp3 in the corresponding folder, there was already an mp3 there! i dont know what i did and when, but there they was! thanks for the tips!