We are so ready to have Google launch Gmail, if only so it will stop all the Kremlin-watching from the news media (us excluded, of course).
MarketingSherpa was the first big trade pub to scrutinize Gmail's ad impact and analyze its potential impact on you and your email campaigns. (AND give you screenshots (with Google's permission)
so you could see for yourself what the interface, copy and ads look like.)
Now everybody's getting into the act, especially the New York Times with its latest investigation (register first)
analyzing which emails get which ads and which ones don't. This article does go deep down into which ads show up where but doesn't shed all that much new light.