While struggling to get all the links together and the correct version of all the accessories to .NET 3.0 RC1 (as this is what BTS requires).

I wanted to develop Workflow based solutions as well and noticed my friend Paul Andrew has read my mind in his post HERE

Here's a snip:

• Install the .NET Framework 3.0 RC for Windows XP and Windows Server 2003. This is not required for Windows Vista since it already has the .NET Framework 3.0 but you do need to ensure you are using the RC of Windows Vista to get the right build of .NET Framework 3.0.
• Install the Windows Vista RC SDK from which you get help documentation and SDK samples. This install isn't required for .NET Framework 3.0 development as you can view the SDK documentation and access the SDK samples online.
• Install the Visual Studio "Orcas" CTP which includes tools for WPF and WCF. Of course you must already have Visual Studio 2005 installed as this CTP adds to it.
• Install the Visual Studio 2005 extensions for Windows Workflow Foundation. This is the matching part to "Orcas" but for WF. If you aren't planning to use WF then you don't need this, and if you aren't planning to use WPF or WCF you don't need "Orcas".
• Install the Expression Interactive Designer matching RC build. This is for creating WPF user interfaces to be used with the "Orcas" tools in Visual Studio 2005.
• Install the Hands on Labs for Windows Workflow Foundation.

I have a Windows Vista RC machine and a Windows XP machine which I've installed these on. It's also the same install on Windows Server 2003 if you use that as your development environment.