I'm not sure if this is news or if I missed it when it happened, but a recent article on RCR Wireless News says Google is testing a wireless version of AdWords in the United States. The service allows customers to place message with links alongside mobile search results.
I haven't been able to confirm this with Google yet. The article also says that Google is working to patent a system for click-through ad placements that determines the type of device used and automatically takes a user to a mobile Web site or places a voice call, depending on the phone's capabilities. Not sure what "working on a patent" means, since you basically submit your application, answer a few questions and fill out a bunch of forms, pay your lawyer and application fees, and wait three years for the USPTO to approve it.
Google launched Mobile AdWords in Japan in April. The AdWords Help Center also contains mobile AdWords help. This press release by mobile advertising network AdMob also mentions Google mobile AdWords.