Microsoft - Upgrade VB5 to VB.NET
This "White Paper" starts out with marketing hype, but then gets into specifics. The "Unsupported Features" section is eye-opening. Some information about upgrading ASP to ASP.NET is also included.

Microsoft - Object-Oriented Programming in Visual Basic .NET
An overview paper written for Microsoft by a InStep, a business partner, this paper is actually a good introduction to OOP in VB.NET. Microsoft wants it to look like a smooth transition, which it isn't, but other than that, it's a great page.