Customs Broker? What do they do?

[davepl]

Apparently, I have to find a customs broker to ship the vehicle I'm importing Edmonton->Seattle. I've got some phone numbers and will start cold calling, but at this point I don't even know what the "Customs Broker" does, besides clearly take some kind of fee for the privilege of me moving something across the border...

Anyone know what the Broker does, and how I go about selecting one?

Not a lot of trucks moving across the border that I can recall, but -someone- must have imported a GMC 910 or something at some point!