This is the position from which Rooney scored his goal in the champions league earlier this week , and if I remember correctly Chelsea had one similar to this not given earlier this season against Blackburn.
Any Referees out there.

Hope this link works

http://i7.photobucket.com/albums/y256/alankearn/DSC00925.jpg

So onside or offside, dont forget there are no defenders BETWEEN Rooney and Ronaldo

Offside, clearly.

Hard to tell from that screen grab but he looks to be behind the ball so isn't offside.

If I remember correctly, he was behind the ball when it was passed so he was onside.

Anyone got a mini-Hawkeye program to run that picture through?

My guess is he's level or slightly in front of the ball, but I know from experience (how many photo-finishes have I called wrong?) that you simply cannot tell from that sort of angle.