<p>ASP.NET MVC has been <a href="https://stackoverflow.com/questions/tagged/mvc">discussed</a> on this forum a few times. I'm about to do a large <strong>migration</strong> of several websites from classic ASP/ASP.NET WebForms to ASP.NET MVC and was wondering what kind of advice those of you with experience in both technologies have.</p>

<p>What I have: a typical ASP.NET app with heavily coupled presentation/business logic, all sorts of messy ASP.NET-generated Javascript cruft, and so forth.</p>

<p>What I want: clean ASP.NET MVC-generated agnostic markup. 'Nuff said.</p>

<p>Any pointers, tips, tricks, or gotchas to be aware of?</p>

<p>Thanks!</p>

Wow, I'm not sure we're talking migration here anymore - the difference is more like re-writing!
As others have also said, MVC is a whole new way to build web apps - most of your presentation code won't carry across.
However, if you are re-writing in MVC what you already have is a good prototype. Your problem is likely to be that it would be hard to do bit by bit - for instance MVC uses URL renaming out-of-the-box, making linking back and forth rather messy.
Another question would be why? Many of us have big sprawling legacy applications that we'd like to be in the latest technologies, but if your application is already working why switch?
If I was looking at a new application right now MVC would be a very strong candidate, but there's no gain large enough to switching to it late in a project.