Google now supports bitcoin currency conversion. You can now simply go to Google and write “1 bitcoin in usd” or “1 btc in usd” and Google will display current exchange rate for Bitcoin.
In fact, it will give you Bitcoin rates for any currency that it is supporting in normal currency conversion.
Oh and you can do USD to BTC too
I tried to find out which exchange rate or symbol it is following to get current exchange rate but their disclaimer does not disclose from where they are sourcing bitcoin rates as of now.
When we try to compare the current rate showing in Google with other exchanges it looks like it is more closer to Bitstamp. But it can be just coincidence for the time being and I am sure it is taking in account more than one sources based on their volume.
In case some one wants Let me Google that for you link :