Well it's probably best to decode them to .wav files if you were ripping them onto a cd so you can preserve the quality (you need a program like MKW Audio Compressor for that -
http://www.etree.org/mkw.html) but if you still wanted to convert some of the files to mp3 after that you could uselots of different programs, two good ones are:
Blaze Media Pro (you can get it at:
http://www.harmony-central.com/Software/Windows/audio_editing.htmlalong with a load of others)
The trial version of audio catalyst is also handy enough(
http://www.xingtech.com/mp3/audiocat...=xingtech-home)