The new downtown YWCA has jumped right into the art swim that surrounds it by throwing open the doors and walls of its handsome new building at 624 Ninth St. NW to the work of 50 area artists. The varied show of drawings, collages and mixed media work was selected by artists Patrick Mohr and Joan Root under the supervision of the Washington Womens Art Center. With luck, it will be the first of many such joint ventures with the artists and galleries that surround the Y.

Another project is also under way: a 10-week course on "The Marketing of Art and the Artist" organized by critic Joanna Shaw-Eagle. It will take place Tuesday evenings, 6:30 to 8:30, starting Feb. 2. For further information and fees, call 229-2188.

More good news for area artists: the National Park Service is accepting competitive proposals for free studio space next summer at Maryland's Glen Echo Park. In exchange for the space, artists are expected to use it daily and demonstrate their skills to the visiting throngs on Sunday afternoons from May through September. Given the shortage of studio space in Washington at any price, this is one of the best deals in town. Call Claudia Lampshire at 492-6282.