The search engine turned web portal turned household name is introducing AdWords for Mobile Search, something that should look eerily familiar to users of the Internet.

With more phones and handhelds having Web surfing capabilities, GPS navigation and search, the opportunity for such advertising is particularly ripe.

Just like the popular Google ads on thousands of websites around the world, this service will have keyword-driven ads to tantalize users with all sorts of buying opportunities. If this kind of advertising is any sort of reflection of the online ad revenue, which Google says was US$10 billion for the year, then the business will be absolutely huge.

The latest news is from Google CEO Eric Schmidt, who told the Reuters agency that “your mobile phone should be free.” He meant, of course, that mobile ads will one day be so popular that they will drive down overall mobile phone costs. We’ll see.