(Or they don't). Preferably just after they stated if they will cut or not, and before the meeting ends.
They dont say anything before the meeting ends and there is no place to get the news any faster then on TV or on a Bloomberg or Reuters terminal.
Any news service will carry it instantly. Worst case, CNBC puts it up right when it hits the newswires.
I'd be checking the TDAmeritrade News Streamer. Also, there's this: http://www.marketwatch.com/search/?doctype=90