w3prodigy

This plugin changes the internal WordPress script queues for the following AJAX Libraries: jQuery, jQuery UI, Prototype, Scriptaculous, MooTools, Yahoo! User Interface, Dojo, SWFObject, Ext-Core, Chrome Frame and WebFont Loader.

Google Hosted AJAX Libraries

Change the internal WordPress scripts to use Google Hosted Scripts

nigro.simone

This small plugin (2 Kb) moves JavaScript to the footer and improve page load times. 
Note: this only works if your other plugins and theme add the JavaScripts correctly.
Configurations are not required! You just have to install it and after the plugin does it all, none further action it’s required.

Speed Up – JavaScript To Footer

Move all the possible JavaScript files from head to footer and improve page load times.

Google Hosted AJAX Libraries vs Speed Up – JavaScript To Footer