MonoX documentation and samples

• MonoX user manual
• MonoX API documentation
• Web part connection sample
• Web part sample

Books

• ASP.NET 2.0 Web Parts in Action: Building Dynamic Web Portals (by Darren Neimke)
• The Web Part Infrastructure Uncovered (by Teun Duynstee)
• ASP.NET 2.0 Website Programming: Problem - Design - Solution (by Marco Bellinaso)
• Professional Web Parts and Custom Controls with ASP.NET 2.0 (by Peter Vogel)

Articles

• ASP.NET Web Parts Controls
• ASP.NET 2.0 Web Part Infrastructure
• Asynchronous Web Parts
• Building Web Parts
• Building Web Parts in ASP.NET 2.0
• Introducing the ASP.NET 2.0 Web Parts Framework
• Personalize Your Portal with User Controls and Custom Web Parts

Webcasts

• MSDN Events Reloaded - Microsoft ASP.NET 2.0 Overview (Level 200)
• MSDN Webcast: ASP.NET Soup to Nuts: Web Part Controls (Level 200)
• MSDN Architecture Webcast: Introduction to ASP.NET Web Part Framework (Level 200)
• MSDN Webcast: Enabling Customizable User Interfaces in ASP.NET 2.0 Web Applications (Level 200)
• MSDN Webcast: Applying ASP.NET Web Parts: Building an RSS Aggregation Web Site (Level 200)
• MSDN Webcast: Introduction to ASP.NET 2.0 Web Part Framework (Level 300)

Blogs

• David Barkol
• Teun Duynstee
• Mike Harder
• Scott Guthrie
• Darren Neimke