Getting live audio into your PC isn’t very hard – most cards have an audio in that works just fine. But what if you want lots of quarter-inch jacks, XLR, and a bunch of knobs? Well, then you need the POD Studio line from Line 6. Line 6 makes amps, recorders, and modelers for musicians and this $280 device, the UX2, isn’t amazingly expensive and should run some good audio through to the included POD Farm software for guitar modeling and recording. Other versions include the single-input GX, and the $210 1-XLR UX1.
My buddy Scott has the Spider III which does incredible stuff to your standard guitar input. It basically changes the entire sound depending on the selected style so you can add tremolo, echo, and crunch at will. Their latest, the Jam costs $449 right now.