ASP.NET 2.0 Web Parts in Action by Darren Neimke
I highly recommend the book ASP.NET 2.0 Web Parts in Action by Darren Neimke (Manning Publications). This book assumes you are already experienced with ASP.NET, so it doesn't waste your time with yet another introduction. Instead, everything in this book is just good content about Web Parts and the Portal Framework, a lot of which is hard to find anywhere else. This book does not just show you how to build a Web Part based Portal, it will also teach you how to customize most every aspect of the process. You'll learn about the Manager control, Connections, and Personalization, but also about changing the look of the Chrome that all Web Parts automatically get. So if you are an experienced ASP.NET developer that is needing to learn about Web Parts, then this is a must-have book -- there's nothing else like it.