A friend and I used to do this, using the USB GPS reciever from Microsoft Streets and Trips, and then an Orinoco PC Card that let us use an external antenna that we got from a Linksys home AP/router.
It was fun seeing all the networks on the map when we got home. I think the original plan was to send out flyers to these businesses offering networking/IT services but we never got that far (especially to the ones with open networks)
I had a magnetic mount antenna on my car and a marine GPS that I used with Netstumbler sometime around 2001. I used an Orinoco PC Card adapter, too. I remember the external antenna connection was very fiddly and fragile. I would run the rig anytime I had a long trip to take. It was fun to see the relatively huge number of networks around bigger cities, as compared to the sparseness of rural Ohio where I lived.
I still remember a few of the more amusing network names when I drive past their locations. I can't ever drive on I-75 south of Bowling Green, OH without thinking of "Chickenfeet".
I had a similar setup that i used while driving cross country ~2002. I used to pull into trucker rest areas to borrow wifi. I had more than a couple ask me about the magnetic antenna.
It was fun seeing all the networks on the map when we got home. I think the original plan was to send out flyers to these businesses offering networking/IT services but we never got that far (especially to the ones with open networks)