http://www.scribd.com/doc/185290302/10-Ways-to-Cut-the-Military-Budget
http://www.scribd.com/doc/185304323/Budget-for-People-Peace-Planet
Basically, these two sites list on how the military budget could be cut by 50%, and we would still be spending more than triple of what China does on their military.
While everything couldn't be implemented overnight(closing down bases around the globe will *eventually* save money)- many of the things listed could be done with a minimum of effort, such as ending the practice of contracting out security to private companies, or ending the duplication of programs that the government already has in place.
Namely 500 billion dollars would then be freed to be able to place back into programs that require funding, such as education, Medicare, etc.