http://henryong.com/workflow-bpm-comparison-chart.htm

http://blogs.technet.com/jessmeats/archive/2008/11/14/sharepoint-business-process-management-i-choose-you.aspx

Sharepoint Workflow Object Model on MSDN

http://www.itconsult.it/sala_stampa/eventi/det.asp?ID=75

Sharepoint can be an excellent foundation for Business Intelligence (BI)

http://www.cmswatch.com/Trends/1488-SharePoint---The-Henry-Ford-of-Business-Intelligence

Jesus Rodrigues has a nice article on Sharepoint Workflow Persistence on http://weblogs.asp.net/gsusx/archive/2006/11/14/SharePoint-2007-Workflow-Persistent-Service.aspx . I'm trying to write a custom Sharepoint Workflow Designer to be used by business people/end users.

How to create custom workflow activities for use in Sharepoint Designer 2007

http://www.ideseg.com/AddCustomWorkflowActivitiesToSharePointDesignerPart1.aspx
http://www.ideseg.com/AddCustomWorkflowActivitiesToSharePointDesignerPart2.aspx

Here is another good post on Sharepoint 2007 custom workflow.

http://www.sharepointblogs.com/tbaginski/archive/2007/03/08/HOW-TO_3A00_-Create-a-custom-Windows-Workflow-Activity-and-make-it-available-in-SharePoint-Designer.aspx

Introduction to SharePoint Workflow!
http://weblogs.asp.net/jan/archive/2004/05/05/126614.aspx
http://weblog.vb-tech.com/nick/archive/2006/09/04/1753.aspx
http://blogs.officezealot.com/jkremer/archive/2006/06/25/11101.aspx
http://weblog.vb-tech.com/nick/archive/2006/07/14/1680.aspx
http://thorprojects.com/blog/archive/2006/11/26/597.aspx
http://www.topxml.com/BizTalk-Orchestration/re-23770_SharePoint-Workflow-as-Commodity.aspx
http://www.timheuer.com/blog/archive/2004/01/16/325.aspx

Decatec Sharepoint WorkFlow services (In Italian !!)