Actually, why couldn't it work like Google? No need for another registration system!

Imagine your GPS device also connected to the Internet (no big advent there). Imagine that clicks-and-bricks operators include their locations' latitude/longitude/elevation/etc info along with phone number, street address, etc. You run an internet search for Starbucks and filter by GPS coordinates from results returned (that could even be a front-end selection). Your GPS location would be a default input. The result set contains hits sectioned off by distance groupings (within 5 kilometers, within 6 to 10 k, etc).

IMO that would be an easy way to implement this without requiring additional infrastructure. There could be other meta data (specials of the day, movie listings and show times, etc) included as well.

All this idea requires is a campaign...

EDIT: heck, some of the groundwork was laid down 4 years ago. An XML standard for GPS data. Duh! Why didn't I think of that before? http://www.topografix.com/gpx.asp