David Ebbo has just posted a screencast covering the Dynamic Data feature in ASP.NET 3.5 Extensions Preview. It is 17 minutes long and covers the following topics:

• Creating a Dynamic Data project
• Creating a Linq to SQL model
• Running the scaffolded version of a Dynamic Data project
• Customizing data validation
• Customizing UI presentation
• Adding metadata to the model
• Writing custom pages in place of the scaffolded ones

Check out David's post.