Most pre-sales start on saturday. Only Bradley Center - Milwaukee WI (February 27) and Bryce Jordan Center - State College, PA (February started today.
Continental Airlines Arena - East Rutherford, NJ (February 10 & 11) and Bell Center - Montreal (February 21) will start on monday and Gaylord Entertainment Center - Nashville, TN (February 14) starts on november 16.
At least that's what A.-XS says.