There is a lot that came out of Where 2.0 and Wherecamp that directly affects this discussion and I’ve been doing my best to digest it all.  Here are some of the highlights:
Google

Flash API for Maps
Feature/Layer Enhancements to Google Maps (Real Estate, Photos, Wikipedia, et al)
Google Friend Connect
REST-based API for GeoSearch

Yahoo
Yahoo Internet Location Platform

Placebase/Pushpin
Free REST-based [...]

BURLINGAME, California — The Openlocation.org initiative launches officially today at the O’Reilly Where 2.0 Conference.
Location technology is driving the current wave of innovation on the web.  With location capability in converged platforms like iPhone, Blackberry, and Android, location will become a vital part of how we find and use information.
Until now, location-based services have focused [...]