I've been messing around with the Google Maps API v.3 for a client of mine. I figure I would share my initial findings:
Clicking a marker zooms in on that marker in google.maps.MapTypeId.HYBRID display mode, and puts the google.maps.Geocoder JSON result on the bottom:
I won’t lie to you: I'm really not sure I'm using the API properly, yet. In particular, I created an array of objects that associates a google.maps.Marker instance with a hash of the name of the state it's in. Then when you select a state in the dropdown, the option's value – the hash of the state's name - is used to select those google.maps.Markers from that array that "reside" in that state. I'm sure the API has a built-in way of handling this, but like I said, this is my first stab at this.
Before you think I broke something or whatever, I've purposely "fixed" the map and made it so it does not zoom with the mouse wheel. This is easy to change. Just look for where I'm setting the MapOptions when creating the google.maps.Map object.
Have fun with the code. The online documentation is good, as are the code samples. I'll keep posting as I garner new aspects of the API. And please comment for other users if you have suggestions, et al.