Anyone tried the Garmin "Spanner" program to allow NMEA0183 over a Garmin GPS USB connection?  It won't install under Vista, but I'm going to try it on my XP UMPC/Garmin 60CSx this afternoon.  Here's the post I read about it on Geocaching.com.

Possibly you know this already, but I didn't, and wanted to forward the recommendation from a friend about this free Garmin software.
I have a laptop with no serial port, and had the need to connect my GPS with USB cable, but NMEA data comes only via serial interface.
Looking for a solution to simulate a COM port receiving NMEA data my friend pointed me to Garmins free "spanner" program.

Though it can only be found on the download page for the GPS 18, it works fine with my GPSMAP 60 CSX, too!

And I believe it will work with any Garmin USB unit, just give it a try!

When you start it, it looks for USB attached Garmin units, asks you which one you want to use, you select it and click the start button, and voila: get a virtual COM port receiving NMEA data!

I really like it a lot and use it now since a week, and it works fine, therefore I'm posting it here now.

Some Garmin units have the capability of transmitting in NMEA format without the software tool.  This is either a selectable function via a menu on the unit or an automatic function. 

My Garmin Gecko can be set to transmit in NMEA and other formats.  My GPS10 automatically transmits in NMEA until it senses a Garmin program running on my computer then it switches to the Garmin proprietary format (unfortunately, this keeps me from running multiple mapping software at once).

When I researched Spanner, I found that the Garmin website had pretty good information on this product.  Click this link and then enter Spanner in the search field.  Garmin only lists the GPS 18 and the GPS 20x in these support articles, but I also believe that other units are supported.