Well..............
The majority of people will say that you should mic your amp and send it through a mic pre-amp to your soundcard line in........
I agree with this but, it's not the way I do it.....
I send the signal from the "headphone" jack directly into the souncard line in....
Of course, my amp only pushes 15 amps.........anymore might fry the PC........ya know?
Micing your amp IS the best way by far........
You need to adjust your preferences in your Control Panel (PC)
before you try it my way though........you need to select "line in" as your preference........it is gonna have a lot of noise this way but, ya get sound........
God I need some gear....
Joe