Variety is reporting (based on anonymous "sources") that actors Paul Rudd and Joseph Gordon-Levitt are frontrunners to play Hank Pym in Edgar Wright’s Ant-Man movie.  The two actors are expected to meet with Wright and Marvel Studios executives one more time before a final decision is made.  Disney has moved up the premiere of Ant-Man to July 31st, 2015 (see "'Ant-Man' Moved Up") and Wright recently tweeted a pre-production photo of a suited Ant-Man character in front of a green screen (see "First 'Ant-Man' Set Photo").  
 
Since the Ant-Man movie might easily involve considerable time-consuming special effects, it would appear that Marvel Studios and Disney have a fairly limited window to get things underway, so a major casting announcement might well be made in the near future.