This post provides an overview for Upgrading VB 6.0 application to .NET
Visual Basic .NET represents a major shift from previous versions of Visual Basic. Because it was designed from the ground up to take advantage of the .NET Platform, there are many areas where compatibility with previous versions is broken.
Things to Consider Before Upgrading
Some of the factors in deciding to upgrade an application include features that aren't supported in Visual Basic 2005, and the amount of rework needed due to incompatibility and architectural considerations. more...
The following book is quite helpfull in
Upgrading Microsoft Visual Basic 6.0 to Microsoft Visual Basic .NET
I will be updating this post with some more details over a period of time..
Upgrading VB6 Projects to VB.NET