I haven't tested it out, but it should work and run obdgpslogger when you have the scantool device plugged in.

This is for obdpro:

BUS=="usb", KERNEL=="ttyUSB*", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", RUN+=obdgpslogger -s %k

If you have a different scantool, it would be cool if you could add yours as well. I've got a wiki going on the openice site with a bunch of udev rules that are useful.