It's not really a surprise, but it was made official in a joint press conference this afternoon; both Ty Lawson and Wayne Ellington have declared for the NBA draft. As they both also declared but withdrew from the draft last season, they cannot do the same this year.
There's not much else to say. It's the right decision for both of them, as neither could improve their draft status with a fourth year in school after their performances this season. I'm sure they'll go on to great things in the pros.
(If I have only one regret it's that, like Groundhog's Day, this means six more weeks of John Wall speculation. Nip it in the bud right now; there's no way, no how he'll choose North Carolina.)