A little while back I made an attempt to find documentation that would help me define the most appropriate way to design .NET projects.  I was aware that it was important to have a Data Access Layer (DAL), a Business Logic Layer (BLL), and a User Interface Layer (UI), but I was unable to successfully find any clear or concise literature to help define architecture guidelines.

Well, yesterday I was very happy to find that Microsoft has released a whole series of tutorials entitled "3-Tier Architecture for ASP.NET 2.0."  These articles were released in June of this year and provide some very useful guidelines on how to get started with a 3-tier architecture in your .NET applications.