...that Obama staff were told to prepare for a VP announcement tomorrow or today, but the same source that passed this along to me expressed skepticism.
My guess? Thursday -- tomorrow -- PM. The event scheduled with Tim Kaine on Thursday is apparently invitation-only, and would not be all that well suited to a VP unveil. If it's going to be Kaine, in other words, Obama would probably need to announce today.
The dead zone in the media cycle is Friday afternoon through Saturday evening ... Friday mornings are relatively normal. An announcement on Thursday evening would allow Obama to get some coverage while people were still at their desks, while also building up anticipation toward his Saturday event in Springfield, which sounds more designed to be a mass media spectacle than for any kind of spontaneity.
And Friday seems to be pretty unscheduled for both Obama and most of the leading VP contenders, creating plenty of opportunities for a joint appearance. For that matter, Hillary Clinton will be in Florida on Thursday and Kathleen Sebelius in Iowa, neither of which are impossibly far away from Virginia for some kind of PM rendezvouses.
With large grain of salt.