Sky's 3D channel will be available to Sky+HD customers on Sky World with HD pack, 
and who have a new 3D-ready TV, from 3 April. Customers who meet these requirements 
should call Sky on 08442 410 092 to request access. Please have the details of your 
TV, including the serial number, to hand.
Once our customer service advisor has activated the channel for you, you should be 
able to see the 3D channel immediately, but you may have to wait up to four hours 
for the channel to appear. When the channel is activated, all you need to do is 
switch your TV to 3D mode (please refer to your TV manual for instructions), put on 
your 3D glasses and enjoy Sky’s amazing 3D previews.
http://www.sky.com/shop/3d/home/faq/

You can see Sky 3D in action at "The O2" in London right now. In the entrance to 
The O2, Sky have created a demonstration where you can experience Sky 3D in familiar 
living room surroundings. The demonstrations are free and available between 1pm and 9pm.