There's a great series of posts on BPMN diagrams at Tyner Blain.

• Foundation Series: Business Process Modeling
• BPMN Diagrams - Introduction to Intermediate Events
• BPMN Diagrams - Make It Right With Intermediate Compensation Events
• BPMN Diagrams - Hit the Links With Intermediate Events
• BPMN Diagrams - Intermediate Multiple Events
• BPMN Compensation Event Correction
• UPDATE: Free BPMN Stencils for Visio 2003

What are BPMN diagrams? They are Business Process Modeling (as-is, to-be, etc) diagrams that conform to the Business Process Modeling Notation Standard.  You didn't know there was an official standard?  Neither did I.  There are even Visio Stencils available.

I look forward to reading the rest of this series.