gman4commerce (welcome, gman!) is kind of right... you get Platinum status for life, 4 eVIP/SWUs, a new status card with "2 MILLION" on it, two matching luggage tags, and a welcome letter. The eVIPs are electronic, and should be good through Feb 28, 2007 expiration date (must USE, not merely commit them, by that date.)

(If you were hitting 1M, you'd get Gold, and 8 of the 500 mile upgrades if you reside in the USA, major differences with 2M or more.)

There has been a lot of rumoring about whether the program will last or not, and some are accelerating their earning rate if they are close to a 1M threshhold, but I won't venture a guess - there have been good points made either way.