What is FIOS?
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.
/johnny
It's Verizon's brand for fiber optic cable to the house.