a player for the appropriate media, a wav editor, a decent sound card with line in, a mp3 encoder, and a RCA --> Phono adapter cable. Here's how to do it:
step 1: connect the source cassette deck, phonograph, etc... line level ouput to the line in on your sound card via the RCA --> Phono cable
step 2: set you sound card to record from line in and use your wav editor to adjust record levels
step 3: play the source media while recording on the wav editor
step 4: edit the wav as needed to clean it up if desired
step 5: burn to an audio CD or encode the mp3 and enjoy
Steps 3 and 4 get a little tedious, which is why I haven't done whis with my entire Cassette/LP/8-track collection.
Here's what I use on my Linux system:
yarec (latest version of Audacity my mean I don't need this anymore)
One note, a Wav editor that's actually good enough to show you the wave form (most worth their salt) would be a good thing. Makes removing hiss and pops a lot easier
A spectre mandates the following disclaimer: Format conversions like this are legal since no protections against it are being defeated, and it is for personal use by one who already owns a legal copy of the media.
Poet and seeker of knowledge