Relationship to BPMN or BPEL?

AFAIK, it has been announced that an activity set will be released through the activity gallery on windowsworkflow.net ( http://www.windowsworkflow.net/default.aspx?tabindex=2&tabid=31 ), that supports both import and export of BPEL 1.1 as long as you limit yourself to this activity set.

As for BPMN, since the designer is supposed to be skinnable, I guess someone could come up with a BPMN skin?

The result XML is absolutely not BPEL.
As Peter pointed Microsft should probably release a BPEL importer (similar to what you have for Biztalk 2004).
Anyway, if you look at the activity set (for sequential workflows) they seem to support everything defined in BPEL, and much more.

I think WWF is a superset of what BPEL defines since you can
a) Define your own activities.
b) create state driven workflow.
The graphical notation has absolutely nothing to do with BPMN.
The designer is is meant to create an executable worklflow not a graphical notation of a process.(as BPMN does)

In Response to Aleksey Savateyev:

The following paper describes a BPMN to Bpel conversion.
http://www.bpmn.org/Documents/Mapping%20BPMN%20to%20BPEL%20Example.pdf

As far as I know there is no way to convert BPEL to BPMN

I do not think there is a "standart notation for BPEL": BPEL is a XML specification not a graphical spec. Every tool uses it's own graphical notation.

Yves, you're right, but that's not what I was referrring to. By saying "BPEL notations" I meant vendor-defined notations. Vendors like IBM have also come up with the mappings from their BPEL graphical representations to BPMN. As you can see in the example that you refrerred to the parallels can be found fairly easily and nothing prevents WWF developers from creating such mapping or a skin as was suggested before.
I also have to say that WWF is not a superset of BPEL - it's above any workflow language. In fact, by just having custom activities one cannot achieve the functionality required by BPEL1.1 spec. You have to have correlation and routing support as well and this of course can be achieved by using custom services, but their implementation is not trivial.
And, of course, standard set of activities for sequential workflows only remotely corresponds to BPEL activities which have different semantics and different attributes to them. Some of these don't even have equivalents in standard activity set, although the functionality can be achieved by using code-beside.

ECLARUS SOFTWARE has a product (to be released soon) that can visualize BPEL 1.1 using BPMN notation. We have free download now at http://www.eclarus.com

If you just want to visualize BPEL for browsing and documentation purpose, you can download eClarus Business Process Modeler for Business Analysts. If you need generate BPEL 1.1 from a well-structured BPMN diagram as well, SOA Architect version is the right choice. We also have a community version solely for BPMN diagram drawing. The community version is free.

Yi