Business Week has an interesting (and rebranded from GameDaily)
article on the growth of in game advertising. Apparently the Yankee group is estimating that the market will reach $732 million by 2010, up from an estimated $56 million in 2005. While it is a bit chilling to think about Master Chief shilling for Pepsi or Coke during cut-scenes the ads do defray some of the higher developmenet costs and I'm guessing after a while people will get used to tuning them out like they do web and TV ads now.