RedKite said...
Carry on is usually not weigthed. If it's not to obvious you get away with as much you can carry if the bag is within the size limits.
I got busted from the xray blokes for having too much in carryon once. I had a bunch of gyros in my bag taking the total weight to 26kgs. I have actually gotten through several times before (dont try this at home kids).
Moral of the story is, you can take a LOT of weight through carryon, as long as you can hide it from the counter although it is pretty dangerous if the plane goes through some 'unexpected turbulance' (particularly above exmouth in a qantas).
Also be warned that if the checkout chick catches you with it and she or he is in a bad mood they charge you big (virgin have a fee for non declared bags).