This is a relatively simple task.
First, you need to record the cassettes to your hard drive ==> simply connect the line-out of any cassettte deck to the line-in of your sound card and record the cassette. If you don't have an audio editing application, the free Audacity will work very well for this.
http://audacity.sourceforge.net/Once you have the recording in digital form, you can use any of several hiss filters to remove the cassette hiss. I've done hundred of recordings from both LP's and cassette tapes, and used some fairly expensive filtering software, but for just hiss you can use Dak's $18 "Click, Pop, & Hiss Assassin"
http://www.dak.com/reviews/2040story.cfm#getAfter you've "de-hissed" the recording, just break it into individual tracks with your audio editor (Audacity will work fine) and burn a CD from the results. Audacity also provides volume equalization controls -- but don't apply these until after you've de-hissed the recordings.
Note: One of the many audio tools I've purchased over the years is Dart-Pro, a $200 package that works very well, but has a fairly high "learning curve" to use the more advanced features. I was just checking to see what the newer versions cost, and noticed they have an inexpensive package called "CD Recorder" that may work very well for what you want ==> you can record; de-hiss; normalize the volume; and break the recording into its individual tracks all with the same application. Their CD-Recorder program is only $29.95 ... a real bargain if the audio processing features are anywhere near as good as their professional programs. It's the last program listed on this page:
http://www.dartpro.com/Main/new.asp
