HTML5 Mapping And Tiling – Tile5
It is compatible with most of the mapping providers like Google, Bing, Yahoo, MapQuest and more.
Besides the API for mapping, the library is also functional for creating more generic tiling application interfaces.
With the compatibility HTML5 offers, Tile5 is targeted at both desktop and mobile browsers.
Tip: there are very nice demos offered to see the power of the library.