I am just finishing up my Bulldog remote starter, so I had to locate the same module myself to disable the factory alarm when I unlock the doors.
If you are a big guy or have large hands, it's probably best to go through the door harness as throwmearock suggests. The door harness comes through the firewall in a black plastic shield and through a rubber plug behind the fuse box. It is pretty busy back so be patient and careful.
If you have to, the theft warning module is located to the right of the steering column as show in the diagram above. It's a grey box that sits next to a smaller black relay. You will have to squirm under the steering column with your head against the gas pedal (take the necessary precautions). Look straight up or slightly to the left. It has over a dozen wires coming out. Look for green wire with yellow stripe. Everything I've seen so far says that this is the alarm disable wire. Check at the Bulldog site and also at 12Volt. It is tricky to work under there and you are probably going to get some cuts. I used the blue wire taps that you can buy in the automotive store. That way I didn't have to strip any wires and tape.
Still haven't hooked up the disable wire yet. The voltage looks wrong to me. It swings from 0.05V - 0.6V when the starter, trunk pop, or door locks are activated and goes back to 0.05V. I would expect it to stay high (12V and then go to ground to when the remote is activated). Also, can't get my dome light to work off the remote starter either. That line just sits low all the time. Did yours work? Hope that helps.