bw100 - 8:59 pm on Jul 20, 2011 (gmt 0)

Launched in beta last November, with limited availability to advertisers, Adwords Metrics is now launching full-scale:

Google Opens Up Call Metrics, Plans Bid-For-Calls Marketplace This morning Google is announcing that its Call Metrics call-tracking capability is going to be generally available to all US and Canadian AdWords advertisers. ... Powered by Google Voice, ... This would mark the arrival of PPCall advertising on Google and would exist in parallel with traditional PPC bidding. [searchengineland.com ]

and, here's the official Google announcement
[adwords.blogspot.com ]

Call Metrics, a simple way to get more phone calls and detailed call reports with AdWords, is now available to all advertisers in the US and Canada. Availability was limited since the introduction in November 2010, so thanks for holding. Call Metrics works by assigning and placing a toll-free forwarding number next to your ad text on Google search pages. When a user sees your ad and calls the number, AdWords registers the call and forwards it to your business. So far, we’ve connected over 5 million calls for thousands of businesses. And calls generated from ads using Call Metrics last six minutes, on average.

Another revenue enhancer. And, of course, it only works with Google Voice.
And, notice the vague "generally available" wording.

This could turn out to be quite an effective tool for some advertisers to drive traffic.

[edited by: Brett_Tabke at 1:17 pm (utc) on Jul 21, 2011]
[edit reason] fixed link [/edit]