BATTLING BANDS: Garage punkers Rocket From the Crypt, in their only U.S. appearance, will headline the national finals of the Underground Garage Battle of the Bands tonight at 8 at Irving Plaza. The event features 10 regional winners who will compete for a chance to perform at Little Steven’s Underground Garage Festival Aug. 14 on Randalls Island. Little Steven Van Zandt (E Street Band, “The Sopranos”), MTV’s Kurt Loder and the Dictators’ Handsome Dick Manitoba will serve as judges for the show. “American Idol” it’s not. Tickets are $12. Irving Plaza, 17 Irving Place, at 15th Street; (212) 777-6800.