Quantcast’s numbers today show that in the mobile web marketshare field, Android and Apple are becoming the only two games in town.

Data from Quantcast

The mobile web is where the action is at these days and for the beginning of 2010, that action in North America has Google’s Android inching away at Apple iOS’s dominant marketshare.

Quantcast, who measure traffic on most major sites, have posted their findings on mobile device usage.  It won’t surprise anyone that for May, Apple is way out in front of everyone.

But the numbers aren’t all rosy for Apple AAPL .  Even with the release of its very popular iPad and two-million devices shipped in the first two months, Android is catching up, and significantly.

In January of 2009, the iPhoneOS had almost 80% of the market.  Over the past year an a half (since the Android platform launched), that has eroded to 58.8%.  Meanwhile, Android has come from almost nothing to last month getting 20% of the North American web consumption pie.

While te rest of the market was mostly  flat for the first half of 2010, Android nabbed 5% of the market from the iPhone OS.  That’s pretty incredible considering Apple’s success wit the iPad.

The numbers for North America are not indicative of the global trends as the iPhone and iPod have a much broader footprint than the 18-month old Android platform.

The numbers may soon take another turn, however, with Apple set to release its much-anticipated iPhone 4 next week which boasts improved speed and display.

However, Android continues to grow with it just today landing a solid phone on Apple’s home network, AT&T.