Found a link on Reddit earlier today stating that Mojang will be releasing Minecraft 1.6 next week. Look like it's officially been dubbed the "Horse Update". I think I might have to jump back on for a while and check it out!
Apparently by "next week" Mojang meant "July 1st". Not that I'm surprised that they'd miss a target date...
Don't worry, even with a delayed launch, there will be plenty of game-breaking bugs, and there will be at least two updates rushed out the door in an attempt to correct some of them.
Looks like you're right, 1.6 was released this morning as 1.6.1. Looks like they found bugs in 1.6 before they even released it. At least they caught them then?