open any of the bitcoin exchange services website and go to your trading area where they have orderbooks and charts and you'll get the livest feed you can get
but also there are third parties such as preev.com to get the price quick but updating slowly. or use bitcoinwisdom.com to see live (updating every 1-2 seconds i think).
or if you are a programmer, use any of these exchanges API service to get the price
is there any particular reason that you want something like this?