Pick up an SM57 or 58 and an Audio Buddy preamp (M-Audio, available from Musicians Friend or 8th Street for about $80.00). Add a 1/4" to a 1/8" adapter into the LINE in (not MIC in) jack of your soundblaster card. Should work and sound pretty good.
Or get the smallest Behringer mixer you can ($65 - 70, 2 inputs) and run the phone out to line in. Same result, although probably not as good as the Audio Buddy preamp. It'll work well enough to get you started. It's about where I am these days - I'm running through a Mackie mixer and it works, but is not really quiet. Click on the web icon and you'll get my page. Basic newbie stuff.