Developer Screen Casts

Some very good Developer Screencasts on SharePoint by Microsoft:

Create an ASP.NET Web Part project from scratch and get it up and running within a Windows SharePoint Services 3.0 site.
Building ASP.NET Web Parts for Windows SharePoint Services 3.0

Create a custom page layout using the Web Content Management features of SharePoint Server 2007.
Creating a Custom Page Layout with SharePoint Server 2007

Use Visual Studio to create a custom feature and an associated assembly DLL.
Creating and Testing Features with Windows SharePoint Services 3.0

Create user-defined content types using inheritance, and then configure a document library to use these content types.
Creating and Using Content Types in Windows SharePoint Services 3.0

Create a list item receiver class to handle both synchronous events as well as asynchronous events.
Creating and Using Event Handlers in Windows SharePoint Services 3.0

Create and reuse site columns across the sites within a site collection.
Creating and Using Site Columns in Windows SharePoint Services 3.0

Discover the integration that exists between Document Information Panels and content types in
Windows SharePoint Services 3.0.
Creating Custom Document Information Panels

Create an add-in for Excel 2007 and then customize the application-level custom task pane.
Creating Custom Task Panes in Visual Studio Tools for Office "v3" June CTP

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

Leverage the new built-in features for creating sites with blogs and wikis.
Creating Windows SharePoint Services Sites with Support for Wikis and Blogs

Understand the difference between page templates and page instances, and then learn how to customize your pages.
Customizing a Windows SharePoint Services 3.0 site with the SharePoint Designer 2007

Create an add-in for PowerPoint 2007 to customize and modify the ribbon.
Customizing the Ribbon with Visual Studio Tools for Office "v3" June CTP

Create a shared add-in with Visual Studio 2005 that extends the new user interface with a custom ribbon.
Extending the Office 2007 UI with a Custom Ribbon

Create a shared add-in with Visual Studio 2005 that extends the new user interface with a custom task pane.
Extending the Office 2007 UI with a Custom Task Pane

Generate, read, and modify documents without going through the object model of the hosting Office application.
Generating Office Documents using the New Open XML File Formats

Configure Excel Services so that you can publish an Excel spreadsheet to a Windows SharePoint Services 3.0 site.
Getting Up and Running with Excel Services

You may also interested to see Videos On SharePoint Designer