BlizzCon have announced the dates for ticket sales. If previous years are any indication, you're going to have to get your tickets almost immediately or not at all -- last year 20,000 passes sold out in less than one hour total.
Regular tickets will go on sale in two batches; the first round will be on on May 21st and the second on May 25th, and each pass is priced at $175. If you're feeling like splurging, you can wait until the 28th and spring for a benefit dinner ticket for $500. These tickets benefit the Children's Hospital of Orange County and grant you access to a pre-BlizzCon dinner with members of the Blizzard team in addition to granting you that coveted BlizzCon pass.
Finally, you can watch from the comfort of your own home for $39.99 thanks to a virtual ticket. Virtual tickets will get you comprehensive live streaming coverage, and the dates on that one are coming soon. Check the BlizzCon site for all the details.