I just got my Webplayer running RandMcnally's street finder GPS (The NEMA 2.0 receiver) I used the Belkin USB to serial converter.
I had to load Windows ME instead of Windows 98, I couldn't get 98se to get the USB ports to work, it took ME to fix it (This might be the first time Microsoft actually fixed something!)
Made a converter from USB to PS/2 for the power, the GPS receiver has a seperate ps/2 power connecter; I connected the two power lines off the USB which are +5 and ground to the pins 4 (positive) and 3 (negitive) of a ps/2 connecter.
I ran the power off my cig. lighter to a power inverter and used the 100ac pwr supply that came with the webplayer.
All pretty cool, I used the usb converter instead of the MAx253 converter on the serial ports so that I could switch it between my webplayer and my i-openers. I now just need to figure out a way to better mount the Webplayer to protect it from vibration; sitting in the passenger seat won't work for long! It would be slick to get it to display on the windshield like a Oldsmobile Cutless Supreme's HUD display but that would take more time and money than I have.