According to your friend and ours DJ R3hab, Rihanna's next single will be 'What Now'.
Tweeted by a Rihanna fan about his remix of said song (which you can preview here), R3hab was asked if it was her next single to which he replied, "yes!".
Then asked when it would be on iTunes, he replied: "very soon".
Surely there's a new album on its way now?