Earlier today Jens from Mojang revealed that username switching would be coming to Minecraft for the PC soon, but that's not the only big news he's sharing. He also tweeted, "FAQ no. 2: Minecraft PC 1.7.6 will be out in March, but 1.8.0 unknown (best guess: May). MC:PE 0.9.0 also unkown (best guess: May)." Not much else to discuss there, but it is interesting that Mojang is pushing 1.7.6 out before the 1.8 release.
For those wondering ,the PC update will have support for the new skin format (with the different layers, among other things) and support for name-changing. Of course we will have to wait until Mojang flips the giant lever in Sweeden to enable name-changing, but it appears 1.7.6 will be the minimum release required to see the updated names.
On a similar note, Jens confirmed on Twitter that he doesn't know when any updates for Minecraft for PS3/PS4/X360/X1. He said on Twitter, "FAQ no. 3: I don't know dates for Xbox / PS3 updates, or release dates of the Xbone or PS4 editions. It's more exciting that way, eh? ;)"
Source: Twitter