Verizon offers internet (and tv and phone service) by running fiber optic cables directly to your home. In contrast, cable companies only run fiber to the node, as a previous poster mentioned. FIOS has a lot more bandwidth available than any of the cable companies, and even offer a 20 Mbps upload/download service both ways, although that costs a pretty penny right now.
Unfortunately FIOS is not widely available, due to the fact that setting up the fiber is expensive. AT&T is also rolling out a similar service called U-Verse, although it will be structured under a similar “fiber to the node” system as the cable companies, since AT&T doesn’t want to spend more money building a similar network as Verizon.
I'm fortunate in that I have Comcast high speed and Bell South (AT&T) DSL available at my soon-to-be home. I'm going with Comcast initially for TV, Phone, and Cable because the price and performance are a bit better. But I am fortunate to have options.
The next upcoming option, if the price drops, will be internet access through my cell phone carrier, Verizon. They have it in many areas, but it isn't cheap.
One obstacle that exists for AT&T or any other land-line phone company is that in underground installations (in some jurisdictions anyway), the customer owns the wire from the junction box to the house. This is more prevalent in underground installations. Yes, it can be replaced with fiber, but it won't be cheap and could ultimately have a very long payback period. That would make any carrier reluctant to start providing that service. Overhead installations are much cheaper to upgrade since there's no digging and re-sodding involved.