Amplitube=Metal tone
Guitar Rig=Rock tones and effects.

And not really. Amplitube is prolly the closest to a really sounding amp!
so if i conect a guitar plug with a normal headphone end into my pc, my sound card wont blow up right?
no, but you'll have hella latency and it'll sound like crap depending on your sound card.
USB interface. stuff like the toneport or fast track usb.