MCT enrollment is open. I’ve had the privilege to work with a bunch of Microsoft Certified Trainers (MCTs) in my few years here at Microsoft Learning, and have found those I’ve met to be a really outstanding group of people: knowledgeable, generous with their knowledge, and fun (and, um, a little opinionated…). Trainers use their qualifications to teach independently, in-house, or for a training company such as our partner CPLSs; or as IT consultants; or to supplement another role. e.g. there are a bunch of Microsoft employees* who are or have been trainers. MCT enrollment is open now until February 28. If you're interested, find info and requirements here. If you can access the MCP site and you already know the drill, you can apply online here. If you have questions about what the advantages/opportunity of getting certified as a trainer are, maybe hit up the newsgroups to get some answers (and, very likely, lots of opinions…) from MCTs.
*including all-time great