This is rather crude, but it works for me.
Code:
for f in *.mp3 *.flac; do
mv "$f" `echo $f | tr -cd "a-zA-Z0-9\-_\ \." | sed s/' - '/'-'/g | sed s/' '/_/g | sed s/__/_/g | sed s/'('//g | sed s/')'//g`
done
Save the code to a file. Make the file executable (chmod ugo+x) and run the file in the directory with the music files.
jlinkels