Google has extended its immense advertising influence into the realm of gaming, announcing AdSense for Games on Wednesday as a way to bring in-game advertisements to web games.

The search king bought in-game advertising startup Adscape Media for $23 million in 2007.

Google is working with developers and publishers such as Konami, Demand Media, Playfish, Zynga, and Mochi Media along with advertisers Esurance, Sony Pictures, and Sprint. 

The Google announcement displayed Playfish’s WordChallenge, in which a short 15-second video clip from Esurance played between rounds. The revenue generated by the ads will be split between Google and the game company hosting it.

Analyst firm IDC forecasts that in-game advertising will grow from $200 million in 2007 to $1.12 billion in 2012. Considering that the majority of players of web-based games spend at least an hour per session, IDC also predicts that by 2012 half of the money spent on game advertising will be in-game.

Google made yet another move to expand out of search engine advertising through YouTube. The search company on Tuesday said it would use the popular video-sharing site to start selling music and games in a partnership with Amazon and Apple. People watching a video ad of EA’s Spore, for example, will be able to go directly to Amazon’s Spore page to purchase the game should they like what they see.