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.
WebSockets supported in iOS 4.2 by Jim Bergman is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://jimbergman.net/about.