Screencasts for Windows SharePoint Services V3...

It's here  on the "Learn Windows SharePoint Services" page.

Creating and Deploying a FeatureStep through the process of using Visual Studio to create a custom feature.

Creating and Using Event HandlersCreate a list item receiver class to handle events.

Creating Custom Document Information PanelsIntegrate Document Information Panels and content types in Windows SharePoint Services V3.

Creating Custom Workflows with SharePoint Designer 2007Build a custom workflow using SharePoint Designer 2007.

Customizing a Site with SharePoint Designer 2007Understand the difference between page templates and page instances.

Getting Up and Running with Excel ServicesPublish an Excel spreadsheet to a Windows SharePoint Services V3 site.