Google is currently testing a new system on Adwords that could prove very popular indeed. Basically you see a small phone icon nest to the advert and if you click it you can type in your telephone number and it connects you free of charge to the advertiser.
Here’s a screenshot:

In Googles owns words:
“What’s the phone icon on Google search results? How does it work?
We’re testing a new product that gives you a free and fast way to speak directly to the advertiser you found on a Google search results page – over the phone.
Here’s how it works: When you click the phone icon, you can enter your phone number. Once you click ‘Connect For Free,’ Google calls the number you provided. When you pick up, you hear ringing on the other end as Google connects you to the other party. Then, chat away on our dime.
We won’t share your telephone number with anyone, including the advertiser. When you’re connected with the advertiser, your number is blocked so the advertiser can’t see it. In addition, we’ll delete the number from our servers after a short period of time.
Am I charged to connect to an advertiser?
No. Google foots the bill for all calls - local and long-distance. However, if we call a cell phone number, you may incur airtime fees depending on the cell phone plan. Check your cell phone provider for details. ”
As an adwords advertiser I am interested to know how well this works so as soon as it is available to all I will let you all know my findings.
I have already experimented with putting in our telephone number within the Adwords advert already and it didn’t appear to bring in better results for me.