In Store -> Shipping -> UPS Realtime Rates you could set up the realtime shipping rates via UPS web service.
Please go to UPS website http://www.ups.com/e_comm_access/gettools_index?loc=en_US to sign up an account and get the Access Key. After you get the production Access Key, you can fill out the form for UPS Realtime Rates. Be sure to check the check box "Send to Production Server".