Much as we've all had a love-hate relationship with brick and mortar game stores, some of my fondest memories as a PC gamer have been lining up in the freezing cold with dozens of other gamers to grab the next big collector's edition at midnight on launch day. If you're hoping to have that experience with Heart of the Swarm, Blizzard has created a dedicated page to find launch events in your area .
So far, there is only one event listed for each region. There will be some Blizzard presence in Mexico City, Brazil, the US, Russia, France, Taiwan, Singapore, Australia, and, of course, South Korea. Many of these events will also feature prominent eSports pros. The event in our neck of the woods, in Irvine, California (near Blizzard HQ), will feature MC, Polt, Suppy, and ViBE, with emceeing by Day and Husky.
If you don't live near one of the officially-sanctioned events, I'd recomment the r/barcraft subreddit, which is a hub for organizing (mostly StarCraft-centric) eSports viewing events at local venues. Depending on your area, it's not always 100% dependable, and tends to be US-centric, but most major metro areas have at least one or two. There's also a running list on TeamLiquid with a few more locations, including the Czech Republic, Hungary, Germany, Croatia, Sweden, and Israel.