Long a glittery weekend salsa pit, Club Millennium now offers a welcome respite to Latin rockers who complain they get no respect in Miami. The Doral-area disco caters to the South American kids of the city's western suburbs with a Thursday-night series of the best Latin rock acts from Tijuana to Buenos Aires. Heavy on the frenzied sounds of the Southern Cone, the new era of Rock en Espa?ol began in January 2000 with Argentine underground institution Los Pericos. In March fellow porte?o Fito Paez drew the biggest crowd to date. The fanatic exuberance of Fito-starved fans pissed off the formerly radical rocker as he tried to play a toned-down set of his best-loved tunes on piano with nothing but a bass accompaniment. Flapping his arms like a Muppet, Paez implored the crowd to shut the doors, indulge in an orgy, then listen quietly to his music in the postclimactic calm. Somebody set off the sprinkler system by waving his lighter in the air instead. One way or the other, Club Millennium is letting Miami get its Spanish-language rock off like never before.