Looks like Garmin is starting to release it’s APIs to the public.

This is something that a lot of the posts on the developer forum have been looking for. I have been looking at the slightly hidden Garmin Connect Webservice API’s (http://connect.garmin.com/proxy/activity-service-1.2/) lately and there are lots of great things that can been done with them. Anyone that has a Garmin Forerunner 405 watch will know how great the great the Garmin connect website is. You can analyse your run, down to the nth degree. Great for any ‘Stats heads’ out there. Using the Garmin connect API’s you can now view your Garmin connect content via a JSON rest request to their API.

More details on the Garmin Connect plugin can be found here but here is an over view of the Architecture:

The Garmin Communicator API is a JavaScript framework that hides the details of working directly with the underlying browser plugin. It consists of three tiers, each more user-friendly than the one it builds on.
The easiest to use is the DeviceDisplay which can be added to a web site with just a few lines of configuration code. The next tier down is the DeviceControl which is for JavaScript programmers who need more control over the event model. Lastly the DevicePlugin is a low-level plugin wrapper for developers who need bare-metal access.