ELIZABETH ZIMMER began tap dancing at 7, modern at 12 (with Florence Peters) ballet at 20 (with Martha Wittman) and contact improvisation at 30-something (with Steve Paxton, Nancy Stark Smith, Andrew Harwood and the gang). She was one of the founders of the Halifax Dance Co-op in 1973, and is happy to see that it is still functioning. She's been writing about dance since her student days at Bennington, and after a stint at the late Los Angeles Herald Examiner and then the L.A. Times, is now the dance editor at the Village Voice and a critic for the Philadelphia Inquirer.