Word today from the Official Google Mobile Blog, Adwords advertisers can now target their ads to searchers using iPhones, G1 or other mobile devices.
Now, advertisers will be able to display ads exclusively on these mobile devices, create campaigns for them, and get separate performance reporting. If you prefer not to show your desktop ads on these phones, you can opt out and show ads only on desktop and laptop computers.
The upside here is that real estate advertisers who are aggressive targeting city-level or neighborhood level searches can create unique campaigns with mobile-ready landing pages as well as mobile-specific calls to action (e.g. “Call 1-800-XXX-XXXX for help with your home search).
This video posted by the Adwords team goes into more detail about how you can set up one of these campaigns.