I too have been transferring music to CD, in my case recordings of
organs which I made myself and were on cassette tapes.

I acquired a program for the PC called 'Audio Cleaning' which is
available on web site http://www.magix.com/  The program has all kinds
of clever digital cleaning and enhancements, which were capable of
restoring clarity from scratched vinyl records and muddy cassettes.
The program allows the resultant media to be stored as mp3 or similar
format and also allow burning of CDs.

Hope this helps!
Best wishes
Stephen Simpson
www.happycowmusic.co.uk