Tickets for the 4th BlizzCon (Blizzcon 2009) will be going on sale May 16th, with live coverage of the event on pay-per-view, and also on internet stream (new!). It takes place in the Anaheim Convention Center Aug 21-22. Tickets will be on sale for $125 US, and a second block of tickets will be sold May 30th for those who miss the sale on the 16th.
Who knows what secrets Blizzard has up their sleeve this year. Here is hoping they sell a life sized gnomish flying machine.