Remote starter prep package??

Just bought a new 08 Sierra. Has remote starter prep package.
What do I have to do to add remote start???

Buy the special key fobs and have a dealer program/activate it. Its available as an accessory.

A dealer parts man should be able to provide more info.

Remote Start - Includes 2 Replacment Key Fobs Only
[17801236] $197.93
http://gmaccessoriesstore.com/images/pixel_trans.gif http://gmaccessoriesstore.com/product_thumb.php?img=images/17801236A.jpg&w=72&h=80
(http://gmaccessoriesstore.com/images/17801236A.jpg)http://www.automotiveforums.com/vbulletin/product_thumb.php?img=images/17801236A.jpg&w=72&h=80
Click to enlarge (http://gmaccessoriesstore.com/images/17801236A.jpg)'); By pressing a button on the key fob, the remote start system starts your parked vehicle from up to 200 feet away. Great for pre-warming or pre-cooling your vehicle. Seamlessly integrated with your vehicles anti-theft and remote keyless entry systems. Replacement key fobs only not a remote start system.