I've used a few different scanner/reset tools, almost exclusively on BMWs though there should be some similarities to other cars (with OBDII, there's supposed to be...).
Peake Tools makes a code scanner reset tool that it very portable and takes up next to no room in the trunk of an ///M Rdstr. Very good product. They also make an SRS (airbag) reset tool, and I carry that on trips also. These are both about the size of a salt/pepper shaker. I have the adapter cable for the scan tool, so I can use either the 20-(21?)pinport under the hood, or the OBDII port inside the cabin.
AutoEnginuity makes a decent package that connects to your laptop (USB or serial port) and depending on the "enhanced" versions for a particular car, can get very deep into the codes and resetting of them, including SRS modules. Contact them for details on particular marques.
My current favorite, is AutoLogics, and is a stand alone computer. This one is a little bit beyond the scope here, but it also reads/resets just about anything on the car, as you's expect for about $10k (mine is a complimentary demo unit).
There are other laptop-based units, but their names escape me; GT1 perhaps?