Cross-posting here and in the Arrow thread on the spin-off series.
The CW has announced that Barry Allen will be appearing on Arrow for the second season of the show.
The CW Plans ‘Arrow’ Spinoff ‘Flash’ Series, Wonder Woman Hold-Up - TVLine
Looks like the plan is to tell the origin of the Flash on Arrow before spinning him off to his own series. I don't know if any of this will carry any weight on the DC movie universe, but if they're smart, they'll blend it all together. Arrow already has a more "grounded" tone like they seem to be shooting for. Put your big hitters on the big screen - Supes, Bats - put the next tier on the small screen - Green Arrow, Flash, Lantern, Wonder Woman - and then pull them all together for one grand JL movie.
Anyway, whether that all happens or not, Barry Allen on Arrow and then spinning off to a new Flash TV series is all coming.