I have a 2001 Jimmy and my vehicle has done the same thing in the past few days. Three days ago I had my ABS and Parking Brake lights both come on. Sometimes they would flash, sometimes one would be on and not the other, sometimes both would come on and stay on. Took it to the dealer, they spent all day working on it and did not fix it, but felt the need to charge me $200 for their labor. Ridiculous! I used to work on my vehicles myself, because I had the time and it saved money. Now it is easier to take it to a dealership, but they are expensive and dumb, at least where I go.
Anyway, I noticed right after both my ABS and Brake lights came on, once I braked hard to see if the ABS was working and when I got stopped, my battery and security lights came on, the fuel gauge went to E and the Low Fuel light came on. My temp gauge and oil pressure gauges also dropped, but nothing else. The radio didn't go off, the vehicle didn't die, just the gauges went crazy for a few seconds and then went back. I have just noticed it since my ABS and Brake lights came on, so I figured it might be some kinda of big disaster under my hood and all related somehow, but apparently a lot of people have this problem.

I personally believe that the new technology is nice and all, but make sure the technology is going to work before you slap it on the vehicles. I am an engineering student and I would almost feel ashamed to work for GM after I graduate. The are so worried about putting new technology in the cars for the future, they can't even make a quality car today. Not that they ever could anyway. The more you put on a car, the more there is to have trouble with though, that's true for anything.