Alarm System?

Hi,

Anyone ever put an alarm system in by themself?
I was going to get it installed by Circuit City but they want 100 bucks plus the cost of their "own" alarm system which is 130 cheapest.
So its gonna come down to about 250 bucks total for the cheapest alarm they have.
I bought a Commando alarm system from slickcar.com and so far it seems pretty easy.
In order for the starter disable to work do I have to buy the starter disable relay?
The system is one of those cheaper ones that works on 12 volt.
For ex. If someone was to open the door and the dome light came on, the alarm would sound.
Or if someone was to try to start the car it would disable the starter.
Does anyone know what wire under the dash goes to the domelight?

Thanks,
Owen

We just had a thread about this, here you go:

http://www.automotiveforums.com/vbulletin/showthread.php?s=&threadid=101076