No one knows when it will get released.
We never know when it's going to be released at console launch. Rockstar never says until a while after.
There has been no official announcement or confirmation, but that's normal.
Everyone knows they're working on it. While there has been no official announcement and they won't talk about it on the record, they're also not trying very hard to hide the fact that it will be released for PC later on. They posted job listings to quote "bring the latest console releases to PC" on their website not to long ago. It's pretty obvious that means porting GTA V.
Probably 6 months to a year. That's about the average range for a GTA game to go from console to PC release. Also, they have to port it and they always update the graphics and add a couple of new features to the PC release and that takes time to do.
Every GTA released on consoles since GTA III has been like that and GTA V will be no different. [The first four GTA games were on PC first or concurrently with PS1, GTA I, II, London 61, and London 69.] Some time next year around spring or summer most likely.