Jay Rasulo, Disney’s CFO, said earlier this week at an investors’ conference that Disney is finalizing plans for a possible Han Solo origin movie, according to the Las Vegas Guardian Express.
Disney has previously announced plans for stand-alone/ spin-off Star Wars films to be released between installments of the new trilogy (see "'Star Wars' Origins Films"), but it appears it won’t be Yoda or Boba Fett as the subject of the first film (though those will follow if this one banks well, according to the report).  The first feature will focus on the early days of the rogue smuggler from Corellia.
Though there is no direct quote, the article says Rasulo told attendees at the investors’ meeting in Beverly Hills that he "made a promise that new Star Wars movies would be released filling in the gaps between the releases of the main saga franchise. This means that after the release of Episode VII due for 2015, origin movies will take the center stage beginning with the story of a young Han Solo and how the character later joined forces with the other Star Wars protagonists."
The movie in question, whether it is about Han Solo or not, is being scripted by Lawrence Kasdan (see "Stand-alone 'Star Wars' Films"), who wrote Empire Strikes Back and is currently working on Episode VII (see "Kasdan, Abrams Take over 'Star Wars VII' Writing").  The only other detail that has been confirmed (by Disney CEO Bob Iger) is that the movie will take place in the years between Episode III: Revenge of the Sith and Episode IV: A New Hope.