I’ve been on the road, so I missed linking to this earlier. DC has posted some Brightest Day info — featuring MAJOR SPOILERS for Blackest Night #8.
In short: twelve heroes and villains were resurrected, with no apparent pattern, by the white light. Among them: the original Captain Boomerang and (as expected) the Reverse Flash.
DC describes The Flash‘s connection to the event like this:
In THE FLASH, Captain Boomerang will deal with a bizarre change he believes is left over from the black ring that animated his corpse. And the Reverse-Flash won’t be gone for long… but he’ll appear somewhere else first.