If you are a bit of a techie, it isn't too hard to do it at home. You need to have a good cassette player, a line-input to your computer or laptop, and software such as audacity, which is free. You generate large wave files and it's up to you to decide what to do with them, convert them to a less sizable format or not, and how you want to listen to them.

I converted a lot of old reel-to-reel tapes, LPs, and cassettes to WAVE files and then broke them into tracks and converted the tracks into mp3s. Listen to them on my portable player.