Obama getting ready to announce his decision, with Democratic sources continuing to say “Watch Biden.”

2 Republican sources say McCain has apparently settled on Romney as his pick, but no offer has been made.

And/but: NY Times: “People close to the campaign also floated a wild-card choice, Gen. David H. Petraeus, the top American commander in Iraq.”

Plus: Politico reports McCain will hold a major rally with Romney, Huckabee in St. Louis the Sunday before the GOP convention.