There is more than one way to do this. Here is the basics. You will need to connect your cassette player into the "line in" jack on your computer.Then to record your sound from the sound card in the computer you need a program such as http://audacity.sourceforge.net/.With this program you can record and edit the sound. Then you move the output file from Audacity into a burning program such as Nero to burn the CD. I hope this will get you started. Good luck.
[bold]I always use MUSICMATCH, as it has a LINE-IN recording function that allows you to record your cassette recording directly to its' library and then you can burn to a CD. You can also convert these files to Mp3 or wav files.