Romney's announcing it today at 9 AM EDT aboard the USS Wisconsin. If that isn't a clear signal that it's going to be Paul Ryan, I don't know what is. Intrade agrees, with the GOP VP market surging to 75% for Paul Ryan.
I'm glad Romney went bold. The WSJ already endorsed Ryan for VP and I think the nearly unanimous praise in conservative circles nudged Romney to make the pick.
I think it's become very clear that Romney wants to really go with the "big ideas" theme, because you can't pick Paul Ryan and not talk about his plans to reform Medicare and Medicaid, which are the two fastest growing programs in the Federal government.
Edit: Intrade's market now has it at 94% for Ryan.