I had my old D1x tethered to a Garmin GPS III for automatic Geo-tagging. Cost me about $80 for the GPS and the cable.
I never managed to get a 10-pin adapter for my D200 when I sold the D1x, it was just cumbersome to have a DSLR and a Garmin tethered (I never had a flashmount cradle for it). A lot of people use the gecko with a 3rd party flash-mount cradle attached to the D200.
Another option I found superior and actually use: When I sold my D200 for a D2x, I also bought a N2 Di-GPS, a little guy that connects to the flash slot and connects to the 10-pin of the D200, D2x, D300, D2hs, and D3 series cameras. I believe Di-GPS has a version for certain GPS-enabled Cannon cameras.
Every time I go in the wild to take photos, the Di-GPS is attached to my D2x.
My Di-GPS was $65 on the 'bay, small, with high sensitivity receiver, and allows me to use my hand held without it being tethered to my DSLR.
Here is the N2 attached to a D200 to show you the compact size:
http://www.di-gps.com/di-GPS/n2.htm