Here’s what I would like to do :
http://www.google.com/maps?start=geolocalize_me&destination=some address here
Google would know that the keyword “geolocalize_me” means that it should geolocalize the person and adds the direction afterwards.
Is it possible?
You would want to use the Google Maps API and the directions service, along with HTML5 geolocation. You shouldn’t try to link directly to directions in maps.google.com as parameters are undocumented and subject to change.
Here’s a sample that uses geolocation to find a users current position.