There have been a couple of reports of compilation failing with MinGW. You can solve this in two ways - Either upgrade your Win32 API headers to atleast 3.7 OR use the binary package which comes with a fix for the compilation. Note that you won't be required to upgrade your Win32 API for the final 4.3.0 package.
Commercial Commercial binaries should be available in your distribution directory.
There are two binaries for Windows - One with Direct3d support and one without Direct3d support. The package with Direct3d support requires the Direct3d runtime. IMPORTANT : Without the runtime, none of the programs in the package will run. You need a fairly recent runtime - Use this NOT this). Once installed, you can start any Qt program with the -direct3d argument to see the Direct3d paint engine in action.
Note: Qt's dependency on Direct3d run time when compiled with "configure -direct3d" has been removed in the snapshots. The limitation exists only in the beta.