Option 1
Depending on your soundcard, I have a Soundblaster PCI-128 on my Pentium 2, which I use for this purpose. The Soundblaster software CD also has a program called Creative Recorder. Choose "Line" (line in). It works like a cassette recorder. Real easy to use. It even has auto levels option. Saves as 44.1 khz 16 bit WAV.
Option 2
There is a freeware called CDEX, which primary functionality is to convert WAV to MP3 ( or other formats ) "from" and/or "to"
It also has an Audio Recorder function.
However, here's the bonus feature. You can save to any format. WAV/MP3.
No conversion is required, if you want to record directly to an MP3