it's called a tethered internet connection. this used to be possible over att/cingular/tmobile for free, but they've recently made it only possible if you add it to your plan. this is in addition to edge. i'm sure this is possible, or will be possible with the iphone, but I personally don't think it's worth it.
if you want mobile internet on your laptop, get one of those antenna cards for whatever wireless carrier you prefer. they are faster, but probably a bit more expensive than a tethering plan.
sorry to crush your dreams, but mine were crushed when att started charging for tethering. i had been doing it for years
