Adsmobi has released a whitepaper entitled USA: The United Smartphones of America.

Smartphone numbers, adsmobi notes, will continue to enjoy incredibly strong growth in the US, but it will be the iPhone and Android that dominate the market moving forward. There will be a total of 117.9m smartphones in the US in 2011, rising to 155.6m in 2012, with smartphones becoming the dominant device category in 2012.

This growth is having a phenomenal impact on mobile internet usage. In 2011, mobile internet penetration reached 41 per cent in the US (129.99m users), and will hit 48 per cent in 2012 (158.9m users). This is generating an incredible uplift in inventory, and having a powerful impact on mobile advertising spend.

Mobile banner ad spend will be $439.97m and accounts for 33 per cent of total mobile advertising in the US in 2011, worth $1.34bn. mobileSQUARED forecasts that the total mobile advertising market in the US will jump to $2.01bn in 2012, when mobile banner ad spend will contribute 32 per cent of spend, generating revenues of $649.1m.

You can download the whitepaper here.