Some Google advertisers received a mail that informed them about Google AdWords' extension to the mobile space:
In the next few days, your search ads will be eligible to run on Google Mobile Search pages (like they currently do on Google.com). We are offering this feature - and any resulting clicks - for free through November 18, so you can experiment with the rapidly growing mobile platform while still reaching qualified customers.
Each ad’s eligibility will be determined by its landing page and only ads with landing pages that can be adapted for viewing on mobile browsers will be shown. (...) Again, you will not be charged for clicks on these ads until November 19, at which time we will begin charging the usual CPC prices. And as always, you may opt-out of this feature at any time.
Google will automatically adapt the landing page the same way they do with search results. This is a better idea than the previous iteration of Google's mobile ads that required to have a mobile-optimized web page. The new mobile search ads will be available only in the US, so if you spot one and manage to take a photo, post a link in the comments.
Update: Here's a test page for Google's mobile ads.