Inscription: what is it?

One of Wrath of the Lich King's big ticket items is a new profession: Inscription. However, no hard details have really emerged on what it is or how it works. Here's Blizzard's description from their WotLK press release: "Learn this exciting new profession and gain unique ways to permanently enhance spells and abilities in the game." And here's the most complete description I've seen so far, from 1up:

Wrath of the Lich King will introduce a new profession called Inscription that will let players customize individual spells and abilities in their spell book — to change the cooldown timer on a Fireball, for example, or alter the crit rate of a healing spell.

So it's like enchanting, but for your spells? Certainly has my attention. What do you guys think? How should it work? What sort of materials does it use, and how do you keep it from becoming overpowered? If it's on demo at Blizzcon, I'm sure our bloggers on the floor will come up with more details, so stay tuned.