My colleague Lauren Isaacson just wrote an interesting white paper about the state of the iPhone in North America.  Among the highlights:

• The strongest growth for iPhone users is coming from people making between $25K and $75K. That bracket is growing at three times the rate of those making over $100K.

• 32% of mobile internet users are open to seeing ads on their phone as long as it is in exchange for something of value. Examples can take the form of free applications, access to information, or discounts on wireless bills.

• Tweens and teens are voracious app downloaders. Last Christmas application downloads for iPod Touches far surpassed (172% greater) those for the iPhone as kids raced to populate the screens of their brand new gadgets. This is great way to engage the youth market.

Source: “2010 State of the iPhone in North America,” Curio Consulting, July 2010