How is your braking? Does the car stutter to a stop? If you have a severely warped rotor, you could be heading up the brakes to the point of contracting. I mean, in a perfect world brake fluid doesn't expand with heat, but that car in its 10 years probably has some air and/or moisture in the lines. That'd cause the car to lock up after driving for a while.

Also, if the caliper bore is whack, using the brakes for 20-30 minutes'll heat it up enough to expand and then lock the piston in the bore.

Also, could just be a plain old wore out wheel bearing. Pull the tire off and look at it, if it's that bad, the bearing should be close to dust.

Edit - Regardless, replace the wheel bearing even if it is the brakes. Heating it up that much probably fucked it up.