Problems with the payload being ready in time for the launch on July 29th, has pushed STS-134 past the original final flight in September. But other issues due to temperature, sun angle, traffic jam with Soyuz (the Russians ALWAYS launch when they say they will) and of course money, may even push the final flight into 2011.
From the looks of the "unofficial" crew photo on the left, the guys already look relaxed and will be waiting out the summer to fly. But they may claim the honor of being the last shuttle mission now. There is a crew of 6, so there is an empty seat. I say offer that to John Young! Wouldn't that be cool if John could start the shuttle program and be a participant on the last flight? Just an idea.