Advertising giant WPP Group said today it has invested $3 million in WildTangent, the Redmond video game company started by former Microsoftie Alex St. John.

The money will "enhance" WPP's ability to get its clients' ads into WildTangent's video game advertising network. WildTangent inserts advertising into its games, which are mostly the casual games that people play for a few minutes at a time on their PCs.

I ran into St. John yesterday at Gamefest, who told me that WildTangent's virtual game software is pre-bundled on about 85 percent of the PCs sold in North America, including machines from Dell, Hewlett-Packard and Toshiba. The company is close to announcing another hardware partner, he said.