Well, I have an ariel extension coming out the back of the box and running through to my bedroom TV. You still need to go to the box to fast forward etc.
You can get an ariel extension for a few quid in Currys/Comet/Asda
as above correctly said just run another aerial lead to the second TV, the SKY+ box will have two outputs on the back.
if you purchase a sky magic eye then you can also control the sky box from the other room, they can be got pretty cheap. if you get one without a spare remote you will have to take your existing remote to the other room though