As a follow up to my Project Freewheel and iPhone: mobile compatibility? post, I got some additional information from Autodesk Labs developer, Gyorgy Ordody. Gyorgy referred me to phones already featuring a full-fledged web browsing experience, using the same technology as the iPhone. iPhone uses a technology called WebKit (http://webkit.org). In addition to the Safari browser for the iPhone, the S60 browser (http://blogs.s60.com/) is based on WebKit as well. S60 is used in the latest (since 2006) Nokia and some Samsung phones. For more information, you can also see the WebKit blog: http://webkit.org/blog/ or applications that run WebKit: http://trac.webkit.org/projects/webkit/wiki/Applications%20using%20WebKit.
Although we have not completed our official testing, the current Safari 3.0 beta for Windows with the latest version of WebKit runs Project Freewheel with a few problems on OS X and Windows. Safari is just a shiny Apple front end and a WebKit back end spiced up with some plug-ins. So once you have Safari installed, you can use any version of the WebKit with the front end - basically replacing the WebKit library when you start up your browser.
The currently released version of Safari on OS X (version 2) has considerable problems with Project Freewheel. Leopard will have Safari 3 which is scheduled to come out in October. For now, the iPhone Safari is based on the same code base as Safari 2. Note, that the iPhone Safari will not have Flash plug-in or Java: