http://blogs.microsoft.co.il/blogs/davidbi/archive/2008/07/21/How-to-get-the-context-item-in-workflow-activity-sharepoint.aspx
http://vdcruijsen.net/post/SharePoint-Workflow-running-in-a-different-context-as-the-host-sharepoint-site.aspx
http://blogs.msdn.com/sharepointdesigner/archive/2007/09/30/getting-to-workflow-information.aspx
Q: How to change the Workflow context if e-g- Workflow is restored on another Sharepoint farm?
