This site supports Programming Excel with VBA and .NET by Jeff Webb and Steve Saunders. Click the Samples link to the right to get all of the code samples for the book. The Samples folder contains all of the books samples in VBA and .NET versions. The VBA versions of the samples are featured in print (because we wanted to keep the book length down to 1100 pages or so!), but parallel samples are provided in .NET as well.
There's a significant benefit to parallel VBA/NET samples: by comparing the two versions, you can learn a lot about making the transition from VBA to Visual Basic .NET. I think that is where most readers are coming from. If you are primarily a .NET programmer, please start with Chapter 25 and then work back to the earlier chapters for specific Excel tasks (and corresponding code samples).
Check out the other links to the right for samples from my earlier work, Excel 2003 Programming: A Developer's Notebook, as well as a bonus chapter on InfoPath and a feature that lets you explore the Excel object model online.
Don't forget to sign the guest book to get announcements and updates for the book.
Good luck, and thanks for reading!
-- Jeff Webb