"Developers will get 70% of the revenue from each purchase; the remaining amount goes to carriers and billing settlement fees—Google does not take a percentage."
-Eric Chu
http://android-developers.blogspot.com/2008/10/android-market-now-available-for-users.html
No wonder Google has usually been the last to implement stuff like VOIP and video-chat and SMS replacements and so on. They don't dare do anything without the carriers' approval, even though they have a much bigger market share worldwide.
On top of all of this, the carriers still get to put their crap on Android phones, too. So this is quite unbelievable. Google gave them so much power, when they really didn't have to, because Android was the only real alternative to the iPhone, especially in the early days when these deals were first made. It's the carriers that should've made concessions to Google, in order to get it, not the other way around.