One of my greatest tricks in Google Adwords was using the off site conversion tracking and taking advantage of the phone tracking numbers. Mid-may they announced that the service was being retired. I am trying to find the email because I thought it mentioned more warnings before it was completely turned off and I also thought we had support through Sept 2009.
At this moment it looks like the numbers are dead. If you were waiting to swap them out, do it right now. I am trying to confirm when they turned off. It has to be within the last 3 or 4 days.