Google will allow web developers to load popular JavaScript libraries for their web apps from the company's global server network. Currently the following frameworks are supported: jQuery, Prototype, script.aculo.us, MooTools, and dojo; this selection covers the most popular JavaScript libraries.
Google will provide two ways for loading of the scripts: the first is the standard <script src=".."> tag, and the second is via the Google AJAX API Loader's google.load() method. In both cases, the libraries are hosted on Google servers. Downloading JavaScript frameworks using Google infrastructure will speed up web applications and cut on bandwidth expenses.
Read the official announcement about the AJAX Libraries API here.
The AJAX Libraries API is very exciting and has huge potential to improve an app's performance especially on initial page loads! I wrote a post on my blog where I explored exactly how much the speed would be improved by using the Google hosted version of Scriptaculous. Load time was at least twice as fast!
See my article and the results here:
http://www.ericdelabar.com/2008/05/letting-google-help-with-your-site-pe...