NMC has written a jQuery plugin for Zoomable, Interactive Maps. Each location on the map would be represented by a bullet. Clicking the bullet would bring up more information on the location. Since the locations of the bullets might be highly clustered, zooming into select subregions is possible too.
However, the plugin currently does nothing on its own to make content available to search engines and those with disabilities. And also, right now it is impossible to programatically interact with the map once it is launched. Eventually it will have a simple API to assist in navigation and other manipulations.
Requirements: jQuery Framework
License: MIT License