Today, Sony confirmed that Sly Cooper: Thieves in Time would be released on 5th February 2013, with a European release to follow shortly afterwards, in March. The game will be released on the same day at retail and in the PlayStation Store.
Buying one version of the game will give you a copy of the other version free of charge, in an initiative to persuade owners of either the PS3 or Vita to buy the other platform.
The game was initially announced at E3 2011, and unofficially slated for the 2012 holiday season, but was pushed back to early 2013 to avoid heavy competition. A demo of the game is available in the Ratchet & Clank Collection if you are aching to give it a try.