I was wondering if I can modify the 2005 stock alarm to roll my windows down. Its been pretty hot in socal and I thought this would be great.

 

probably not the stock keyless entry since that is programmed into the keyless entry. aftermarket alarms with their remotes can usually be programmed to do that.

if you want my advice, do what i do, when you leave the car, pop open the sun roof a tiny bit, and close the roof shades to help keep sunlight out. then legally tint the other windows to cut down on solar energy heating up the inside of the car.

 

Just to expand on what drax already said; aftermarket alarms can be programmed to do that but it isn't with the remote alone. It takes additional "window roll-up" modules to do it. DEI 529T or 530T has to be used in conjunction with one of their alarms. It takes 1 to control the windows and another to control the sunroof. You can have it set roll the windows down and open the sunroof as well as roll them up and close the sunroof.