As you may already know Google Checkout recently launched in the UK. Google Checkout has actually been available in the US for just less than a year now and Hitwise have just made available some statistics showing how the take up of google checkout is going so far in the US.
The statistics show that PayPal received 67 times more of a larger share than Google Checkout did. This is not greatly suprising given that PayPal have built up trust over a long period of time.
The statistics also revealed a huge peak in visitors around the period of time when Google launched a big promotion - $10 to $30 off purchases. The same is likely to happen in the UK given that Google are similarly offering £10 off purchases of £30 or more.