Lights-on Warning

Best way to do this is to get an integration kit.  They run on the pricey side but are well worth it in my opinion as they let you retain all of the car's functionality.  I like the bestkits product the most. http://bestkits.com/bk_did_you_know.htm

Here's a lil blurb from their site:

BKA2004T This exclusive relocation harness is for aftermarket radio installations in 2000 and 2001 GM vehicles that utilize the Class II data bus (including the Cavalier, Sunfire, Impala, Monte Carlo, Venture Van and Grand Am).The removal of the factory radio in these vehicles will result in the loss of the door chimes and other vehicle systems that rely on the OEM radio. There is also the possibilty of the airbags inadvertently being disabled. The BHA2004T allows for the relocation of the factory radio and the installation of an aftermarket unit and retention of these factory systems (17 ft. Harness- Trunk Recomended). Replacing the OEM radios in these vehicles without the use of this harness is a liability and a safety concern.

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Honestly it's gonna be a lot more work figuring out how to do this without using the factory radio (and making it happen!) than it would be to just use the relocation harness.

You can buy that harness here: http://www.installer.com/cars/pontiac.html