I use audacity regularly to cut large mp3 files into manageable pieces, to filter out noise and for cut and paste work.
Make sure you get the livna rpm so you can use mp3. Even so it'll ask you where the lame lib is located, but will ask you to find it opening the directory you should have it installed to anyway.
Some days ago i also posted a 'review' of a great audio script
to convert sound files from one extention type to another or to a different quality in mp3.
I'm looking forward to installing CCRMA myself, but will wait a bit till everything is ready for FC4