I don't think you can unless you already had recovery software installed that uses the gps chip to locate it and then of course, have the gps enabled at the time of theft. At least that is how I under stand it.
You could always get another one if it doesn't turn up.
One place I know that has the best rates in the country for smart phones is a relatively new service provider called FLASH Wireless. They have an actual real unlimited EVERYTHING plan for $59.99 (data, text, calling, long distance the whole 9 yards) and they run it on the Sprint backbone. You can find them here http://richmanson.shopacnrep.com/wireless/index.aspx
They also have deals for all the main carriers also, so I don't know what your personal requirements are but there is one place to look if you looking for something specific.