For some people, myself included, it wasn't very clear that when you created a "character name" when starting StarCraft 2 for the first time that you were actually creating your public username to be used in multiplayer and co-op matches. Thankfully Blizzard realizes that there's some confusion and will be offering a one time name change for free.
After the initial free offering Blizzard is going to launch paid name changes, something they already offer in World of Warcraft for $10.
Anyone going to take advantage of the free change?
Source: Us.battle.net