Wow! I have a similar project going, but I thought that I had it bad with a few hundred tapes :) Prioritizing has been key, since many have the same tunes on them, different versions. It's actually a fairly involved project. My first home recording setup was an old Fostex 4 track cassette machine and a small mixer. Now I've got 150 multitrack cassettes laying around and no machine to play them on. What I do is use my very high quality standard cassette deck to play them into the computer to digitize them, flip the tape over to get tracks 3 and 4, import them into Audacity, reverse tracks 3 and 4 (they are backwards since the recorder recorded all 4 tracks in one direction), cut the tracks up into individual songs, and time shift tracks 3 and 4 to sync up to tracks 1 and 2 (to account for small differences in the digitizing and for tape stretch). Now I have a reasonably workable version of all of the original tracks to edit, clean up, and remix. Most of it was recorded in my junior high school days, so it's just more sentimental than anything, but nice to have. Audacity has been a lifesaver for this kind of work, and I'll be remixing them with Ardour. I don't know if I'll bother mastering them afterwards, since it was pretty lo-fi stuff to begin with.

>I have a fair old pile of old cassette tapes that need going through at some >point. Ug. Fortunately I had a moment of clarity in 2000, when I found myself >in possession of the original 4-track cassette machine, mixing desk and >MiniDisc recorder and dumped all my 4-track demos on to MD. This came in very >handy when I decided to digitize them last year.