My Response:

Audio quality with respect to a cassette tape recorded to a CD will only be as good as the source (tape) and the equipment used to read the tape and input it to the computer ... and of course, the ability to modify the digital recording in order to improve sound.

Two great reasons for recording your analog tapes to digital might include:

• Wear and tear: digital media doesn't lose its crispness and quality over time.  Shelf life is about 100 years for a recordable disc.
   
• Digital goodness: as I mentioned above, the ability to modify a digital recording in order to amplify sound, reduce background noise, and other neat tricks can really rejuvenate lost sound quality... and it's ridiculously simple!

OK -- so how does it all hook up?

Most computers today have sound cards built into them which have a MIC (Microphone) port ... heck, you can even use a Voice Modem with a MIC port to encode digital audio!

Most MIC ports are located at the back of the computer, unless you've got a Compaq / Gateway / Dell -- they're usually at the front.  MIC ports look identical to an "earphone jack" port, are typically red (or pink), and may be labeled "MIC" or have a little picture of a microphone above the port.

If you're recording from a tape player, you most likely have RCA (left and right) audio plugs in the back of the unit, so you'll need a "Y" cable that goes from RCA (left and right) to the Sound Card's "earphone jack" port.  You can pick those up at Radio Shack: just ask someone to help you if you can't find it.

Internet How-to Audio Guides?

I did a quick search on Google for a guide on how to record audio from a tape cassette player to the computer (or similar), but didn't turn up too many decent results.