Lightsout.org is a great place to start.
Though I havent been there in some time(since I diasbled mine), I thought thier was an Alero section but I didnt see it.
If you do this, make sure you DISCONNECT the battery or you might smoke the Bcm.
I would recommend that you remove your glovebox and the under dash panels. The BCM is a black box about 1" thick and 3-4" long.
It will have 3 connectors.. 1 pink and two gray.
Look and see if your Alero is the same color.
May be some one else can verify these wires are the same color on the 99-00 alero's.
I'll post the disable here if allowed!