Mazda5 TCS light and power steering light both illuminated

I got in the car tonight to go to the store and when I backed out of the driveway the rear especially made more than the usual noise of backing up, like the brake pads were continuously scraping the discs slightly. I drove about 100 yards and the TCS light and power steering lights both illuminated. I slowed down, stopped, drove a few more yards and the sound was still there. I pulled over, turned the car off, let it sit a minute, then turned it back on like the manual states. The power steering light disappeared but the TCS light stayed on for another few minutes before itself going away. The sound (pads on discs) also disappeared.

Any thoughts on what's up?

hmmmm sorry don't know what could cause both the TCS and PS lights to go on together, but the dealer should be able to check and reset the error codes, or use one of these:
http://www.harborfreight.com/can-obdii-code-reader-with-multilingual-menu-98568.html

I checked the OBD and there's nothing stored. The car had been pretty cold and the parking brake had been engaged while parked for a day or so, but neither of those should be reason for the TCS and power steering to go off and the brakes to act weird.

If your parking brake was engaged and it was below freezing point, it's possible it just the parking brake just seized (i.e. froze to the rotor).