heres the thing...
you could use the microphone port on your sound card, wich is amplified. BUT it would sound crap!
STILL, there is the line-in port... Wich is unamplified
what I do is run my guitar/bass in the amp then take the line out of the amp into the card's line in... but to get any somewhat audible volume, you really need the amp.......
that does the job with a good sound...... BUT have a low volume on your stuff, like johnH said, because it overloads a lot (i get distortion on my acoustic )
just try it in the MIC port, and maybe, MAYBE the sound will be ok...