Migration / Conversion to .NET Plan of Attack

Does anyone know of any best-practices links or related MS links, or insight on how to go about a large scale conversion from a legacy system to .NET.

We currently have a conversion project, but it is not a straight conversion. It seems as though everything is being thrown into the project (database redesign, n-tier architecture framework, redesign of processes and work flows).

So I was wondering if there is a "best practices" suggestion on how to go about the conversion (what should be done first, what can be done later and have the smallest impact on changing the app once released, etc.). The app is due out before I can finish all the redesign stuff, so I need to pick and choose (with some mandatory) what to put in - and would like to make the best choices so that the smallest impact will be made to any existing applications that I get out before the redesign is 100% in place (architecture, DB, etc.).

Any links or suggestions? Thanks!

I think this is such a nebulous subject and very much really depends on the project at hand. If you could break the issues down then we may be able to point you to some stuff.
Cheers.