http://audacity.sourceforge.net/ This is a good audio editing program, and it's FREE. Give it a try. I like it and have used it for some time. Good luck.
Ditto, Audacity is easy to use - I just started using it this week and I'm already comfortable with it. FYI, for converting cassette tapes into MP# files I found the AMPLIFY effect very helpful - instead of trying to "eyeball" the input meters to maxmize your signal strength without clipping, I record at a middle-of-the-road level (like 0.4 or 0.5), and then afterwards run the AMPLIFY effect - best I can tell is it perfectly increases your recording levels just up to the point where you would risk clipping - its cool to let the computer "solve it" instead of having to painstakenly do this yourself.
