>I can't thank you enough for the most detailed description of your project. If I ever get the time and a good knowledge of C# this would be the process I would follow. Meantime, I will print out your message for more study and a guide.

No problem. Definitely get people to crtically review what I have laid out. There are different ways to do this kind of thing. In doing that way I had a couple of goals:
- I new I couldn't learn everything at once, so learning ASP.NET at one point, then pure C# at another, then SQL Server at another allowed me to learn in chunks
- changing only part of the app at a time meant that it was easier to make it stable. For instance we new that the biz tier code was good and working, if there is a problem, then it is probably the new ASP.NET code
- large projects have a lot of risk. I think gone are the days of 1, 2 or 3 years projects. Technology changesa and our users needs change. There is really no way these days to lock down an app for 3 years while you re-write it. Using my migration technique I was able to break down the largest chunk into 6-8 months. Still too long for me, but that was a short as I could make it.

I am only a single developer with a part time consultant that I can hand tasks off to, so can only do so much at a time. A larger shop might be able to blitz a project in 2-3 months and get it finished.