There's an entire hardware industry built of products that ease the pain of recording audio to a basic home computer. But the truth is, you really don't need things like USB turntables, , or in order to make decent digital audio recordings.
A willingness to experiment and $15 PC microphone or $3 minijack cable should be enough to get you up and running with computer audio recording. The trouble is, most people just don't know where to begin. I can't promise that he followingand will turn your computer into a full-fledged, multitrack digital recording studio, but at least it'll demystify a few things and get you pointed in the right direction.