Kids ages two to fourteen spend $0.21 on digital content out of every dollar's worth of entertainment they buy today, according to a study in the NPD Group's new 'Kids and Entertainment Content, 2011 Edition.' That's up from just two years ago in 2009, when the ratio stood at $0.15 out of the dollar. And they start young; by the age of seven, 50 percent say they have paid for their first digital purchase—with and without help from mom and dad or their friends. "Kids are not skittish to use technology that is available to them," said the NPD’s analyst Anita Frazier.

Read more: Digital game purchases up 17 percent from 2009 »

The July sales numbers from the NPD Group are due tomorrow, and some analysts are already warning that the figures are likely to be dismal. The firm Cowen & Company predicts sales of $317.5 million. This would be a 27% year-on-year sales decline, the worst since September of 2005.

The one ray of sunshine in the expected poor report is NCAA Football 12, which is estimated to have sold 770,000 units -- an improvement of 11% over last year's installment.

Read more: Madden and StarCraft play a role »