Video games are blowing up as one of the biggest segments of the entertainment industry. Movies have been innodated with advertisement placements for a very long time and it's only a matter of time before it becomes as prevolent in video games. The economics work, take a look at this excerpt from "Advertisers get in the game: Consumer products hope to score with visibility in videogames" by Katherine Monk:

"With more than a dozen advertisers, that means EA's Need for Speed Underground 2, which is being developed at Electronic Arts Canada's Burnaby studio, could pull in more than $5 million US in ad sales. But given the high cost of development, it's not enough to help the title break even before it hits the shelves. At least not yet. "

I still remember the Pizza Hut signs in the Nintendo Teenage Mutant Ninja Turtles game.