Boston Globe and other sources reporting that, right about now, Scott Brown will release "a statement."
Typically one would not announce his Senate candidacy with a statement instead of a live event, and the reports are that he has decided not to run, despite pressure from the Massachusetts GOP and the NRSC.
Many observers have speculated he'd rather run for the open Governor's seat in 2014 rather than have a tough Senate race this year and another one when the term expires next year. If so, it's great news for the Democrats. Brown is the one Massachusetts Republican with a good shot at winning this seat.