This video demonstrates how to use the SharePoint Guidance Library's configuration component. Configuration providers such as feature receivers use the IConfigManager interface to set values while configuration consumers such as web parts use the IHierarchicalConfig interface to retrieve values.
the Contoso RI Walkthrough of the Contoso Reference Implementation
How to use the logging components?
How to use the SharePoint Services Locator?
p & p Developing SharePoint Application Guidance
patterns practices--Courtsey MSN Channel9