The command line to use in RadHelp for the MSDN Library for Visual Studio 2008 SP1 now available for free download from Microsoft is
ms-help://MS.MSDNQTR.v90.en
It is entered using "RadHelp options" from the Option menu under winapi.kwl. Once you have the MSDN library installed enter the command above and it will search the MSDN library for API keywords. The MSDN library can be downloaded from...
http://www.microsoft.com/Downloads/details.aspx?familyid=7BBE5EDA-5062-4EBB-83C7-D3C5FF92A373&displaylang=en
When you run setup if you include the embedded development section RadHelp will always display the Windows CE version of the API if available, to avoid this do not install the embedded section.