This morning Google announced that its Call Metrics call-tracking capability is going to be generally available to all US and Canadian AdWords advertisers. Call Metrics is not to be confused with mobile Click to Call ads, though Call Metrics is available to Click to Call mobile advertisers as well.
This opens up a wealth of opportunities for not just larger Paid Search advertisers but also small and local businesses who have a difficult time tracking where therre sales are coming from.
Search Engine Land has a great write up on the whole thing Here!