Anyone out there ever installed anything like this?

http://cgi.ebay.ca/HYPER-BLUE-FLASHI...QQcmdZViewItem

http://www.canadiantire.ca/browse/pr...romSearch=true

Pretty soon I am going to install some sort of blinking LED like this too simulate an alarm system since Im going to be putting a bit more money into my Aveo in the near future and I want to at least deter would be thieves.

The basic instructions say this:
White: Connects to constant 12+
Yellow: Connects to any 12+ accessory wire (12+ when the ignition is on)
Black: Ground to any 12- wire or any screw that is in metal.

I installed a deck, speakers, amp and subs myself including taking apart the doors so Im pretty condident with this stuff. What and where are the constant 12 volt and 12 volt accessory sources though. Do I have to hook a wire to my battery or is there existing ones behind the dash. If anyone has done this before or can suggest a good way to install this I'd appreciate it before I start experimenting.