When the realms come back up this afternoon, patch 3.0.2 will bring with it new talents, new skills, and a whole new profession: Inscription. This is one major Wrath feature we'll be getting early. The new profession will allow players to augment their spells with glyphs, which are ultimately made from herbs. The herb markets on some realms have already surged from people stocking up to power-level Inscription. I'll probably take advantage of the high prices to make a few gold, myself, and become a scribe later when it's cheaper.
But if you are interested in becoming one of the first scribes on your server (which could be quite lucrative), you may want to look at this power-leveling guide over at WoW Economist. It details exactly what you'll need to rush from 1 to 350, and what you can make to do it. In total, it looks like it should take about 72 stacks of assorted herbs, so I hope you're stocked up.