Hi, welcome to the forums.
There hasn't been an official ammouncement, but those in the know reckon it should be available last week in February (Ish)
If i remember correctly, when it came to iOS, it was an update the the existing Sky+ app (the one that allows remote recording) which added the remote control functionality.
Best advice would be to make sure you have current app installed, and then start checking for updates late Feb.
There is a thread dedicated to the subject with regular updates here....
http://forums.digitalspy.co.uk/showthread.php?t=1771795&page=1