Today I'm feeling a bit sick. Rather than write my own post, I'm going to recommend that you all visit one of my favorite sites on the net. Tarou WoW Guides is full of both text and video guides for leveling professions AND using them to profit. The videos are high-quality, the audio is great, and the methods are extremely easy to follow. The profession-leveling guides are very good, they are easy and inexpensive on top of being simple and fast. As an added bonus you'll find some miscellaneous guides, such as 4 Man Flame Leviathan and a general Auctioneer how-to guide.
You'd expect to pay for this quantity and quality. The best part about Tarou WoW Guides is that its entirely free. Get ready to start using your professions for profit.