is there any demo on how to detect geode ,fire eagle, google gear installed on user browsers and get user location?
I've written a brief page explaining different ways for a developer to obtain a user's location, including IP geolocation, the W3C Geolocation API and reverse geocoding.
It's possible that you might want to detect Geode, Loki or Google Gears geolocation as well (although I think those are likely to be phased out once the W3C API is settled on). Ajaxian has built a shim that will abstract out queries to W3C, Gears and Google ClientLocation.
Finally, Fire Eagle is just a location broker -- you can install a Firefox plugin for Fire Eagle, but that still won't provide websites with access to the user's Fire Eagle location. (That would be cool though, I hope they're working with Mozilla on that).