Blizzard has announced via the BlizzCon site that tickets for BlizzCon 2011 will be available for purchase in two batches: once on May 21 at 10 a.m. Pacific time, and a second time on May 25 at 7 p.m. Pacific time. The price has increased (again) to $175 per ticket. Virtual tickets will be available for $39.95, the same as last year.
Those wishing to attend the charity dinner can do so by purchasing the $500 ticket at Saturday, May 28 at 10 a.m. Pacific time.
[EDIT: May 25th ticket sales start at 7 p.m. PT, not 7 a.m. PT.]