My first attempt at jumping into Web APIs, Javascript, and PHP is a little application that synchronizes the views between a Google Map application and a Yahoo Map application. To see it in action, start the Google Map Controller, and the Yahoo Map Follower. Move around in Google Maps and see it updated in Yahoo Maps. That's the extent of the demo right now. For best effect, open two seperate browser windows side by side, or on two seperate computers. More may come later ...
I've put links to the side over there on the left ...
Known issues
Internet Explorer not suppported yet ... Internet Explorer implements some of the javascript code differently. It is fairly trivial to add the code in to support IE, just a matter of time and priority.
Not scalable past a single instance ... I haven't added the ability for multiple independent sessions yet. This is fairly trivial (I think) to do, as it only requires a session id to be created and used by the Controller/Followers, and shouldn't impact performance that much.
No mechanism for arbitrating control ... Multiple Map Controllers can exist simultaneously, which would lead to erratic map behavior as control is given to the last one to finish the map movement. This may not be that bad of a sharing mechanism, but I should investigate more explicit mechanisms.
Underlying code is procedural, not object oriented ... The code is not elegant, lacks robust error handling, and should be modularized.