Some time ago Blizzard announced that a system for paid name changes on Starcraft II was in the works. On friday they communicated that, unfortunately, the project has been deprioritized in favor of focusing on finally putting Heart of the Swarm on the shelves (I'm honestly not exactly sure how the two things are related, but hey, I'm not a game developer) and because of other considerations.
This wasn't exactly communicated to the playerbase, and apparently a few people that really really wanted to change their name weren't too happy about that. As an apology, Blizzard pledged to do a better job with communication in the future and unlocked a free name change for everyone. So if you really really dislike the name you chose for yourself (or you quit your old clan that now is embedded in your name like the tattooed name of an ex girlfriend that cheated on you), you can now change it without spending a dime. Here's how to do it.
If you'd like to change your character name, log in to Account Management and choose your StarCraft II: Wings of Liberty game license. On your game license screen a "Character Name Change" button at the bottom will initiate the request. After confirming that you'd like to change your character name, log in to StarCraft II: Wings of Liberty, and you'll be prompted to assign your character a new name.
Paid name changes are still coming, even if the low priority means that we won't hear anything about them until the release of Heart of the Swarm. In the meanwhile another free name change will come with the new Clans feature (that will automatically add the clan tag to nicknames, removing the need to manually include it) in a couple months.