I follow Baby Jogger on Facebook and yesterday they posted that participating retailers will be selling the Baby Jogger City Select with a FREE second seat. This can save you almost $200 bucks. I know www.albeebaby.com is participating and I don't think Buy Buy Baby is participating. I'm not sure Amazon is particularly participating but they have the stroller with the second seat for $499 (free shipping and no tax).
As much as I'm dying to buy one, we're waiting until we absolutely need it. (We have the Joovy Roo Twin).