My brother bought a SPDIF optical out extension (I think it was 60Marks from Reichelt) for my SB Live and hooks up his MD deck with the optical cable. Since the optical out plays what you hear from the normal soundcard, all he has to do is set up a playlist in Winamp and hit Play and Rec on the PC and MD.
For less quality (its MP3 so you won't be missing too much) hook up the MD to the soundcard, set the recording levels and do the rest like with the optical sollution above.