I agree, earphone out to microphone in is the way to go if you don't want to spend any money. When I converted all my cassettes a few years ago, I purchased a $20 cassette stereo component that had "line out" jacks on it and hooked them to my computer's "line in" so I didn't have to deal with audio levels. I bought it from Goodwill and then returned it when I was done. You could do the same at Target or Wal-Mart - just buy a cassette player with line out jacks and hook it to your computer.
Really, the easiest thing to do would be to buy a cheap digital recorder that has a USB jack on it and record onto that instead of cassette tapes. I bought one from Target last year for $50 and I'm sure you can find them online for $20 or $30. Or if you're calling from home, just eliminate the cassette recorder and plug your TP-7 directly into the microphone jack on your computer.
The best software to use (in my opinion) is Adobe Audition 3.0. You can use this to import your cassette tapes or to record directly from the TP-7. Previously the software was known as Cool Edit and there's not much different between the two other than a slight upgrade to the interface. Both are available on torrents.
