Apple released iOS 4.2 in November 2010, and part of that release was support for websocket in the web browser.
This was confirmed in a visit to a local Apple store. Here are some screencaps grabbed of the iPhone 4:

iOS 4.2 is also available for the iPad, which is a huge improvement. iOS 4.0 was only for the iPhone, and the iPad was still using iOS 3. Here are the iPad screencaps to confirm websocket support on the iPad:

Apple had websocket support in the beta of iOS 4.0, but removed it before release. Whatever reason it was not included iOS 4.0 must have been resolved in iOS 4.2.







