Nice idea on the audio faq sticky, but it seems this thread is somehow evolving into one. But rather than re-invent the wheel, there are sites that give a better explanation on audio technology like tweakheadz.com or even the Bruce A. Miller online mixing courses (the links are in the Educational Material sticky so the faq is kinda covered, albeit via proxy).
Is a laptop good for recording? If it's fast enough and has sufficient ram, yes. But remember, you can't upgrade the cpu and video, and you will need external hard drives for unloading data to. Soundcards can come in pcmcia, usb2 or firewire flavor, but you will have to research your laptop's specs since some chipsets and firewire/usb controller chips don't play well with audio.