From Paul Andrew's Post: http://blogs.msdn.com/pandrew/archive/2007/02/25/Microsoft-provides-BPEL-2.0-in-WF-_2D00_-BPEL-for-Windows-Workflow-Foundation-March-CTP.aspx
In March 2007 Microsoft plans to release a CTP of a set of BPEL activities for Windows Workflow Foundation (WF). This will be called BPEL for Windows Workflow Foundation March CTP and the CTP release will implement the BPEL 1.1 specification. The final release of BPEL for Windows Workflow Foundation will implement the OASIS BPEL 2.0 standard and is planned for release in Q4 of calendar year 2007.
The download will be separate from the .NET Framework and it will be required for developing BPEL based workflows in Visual Studio. The same download will provide runtime operations for executing BPEL based workflows. It will include a set of BPEL activities for Windows Workflow Foundation that will implement the BPEL standard. Import and export tools are provided so that BPEL can be loaded into the XAML format used by Windows Workflow Foundation and vice versa. Visual Studio is not required for the import/export but developers will benefit from using the workflow designer that runs in Visual Studio 2005.
This release shows the extensibility in Windows Workflow Foundation. No changes were required to the Windows Workflow Foundation codebase to support these new activities and other Domain Specific Languages (DSL's) could be also implemented on Windows Workflow Foundation through this extensibility.
How does this announcement affect the support for BPEL in BizTalk Server?
The next major version of BizTalk Server will be built on Windows Workflow Foundation. This was announced back when Windows Workflow Foundation was first disclosed in September 2005. BizTalk Server will be able to take advantage of these BPEL activities at that time to also allow for BPEL 2.0 support. At that time both Windows Workflow Foundation and BizTalk Server will support BPEL 2.0.