Is there any documentation or example how to use MvcContrib.TestHelper.Ui and WatinDriver?
I haven't found any real documentation for it, but there are examples of its use in the source code for the CodeCampServer project. You might also want to take a look at Chapter 20 "Full System Testing" in the book "ASP.Net MVC 2 in Action." It's a really great look at a similar approach to what the WatinDriver is trying to accomplish. Its discussion is also great in terms of designing your UI/HTML to be testable with tools like WatiN, and techniques to help make your browser testing less brittle.
EDIT: The WatiNDriver in use in the Code Camp Project source code isn't technically the one from MvcContrib.TestHelper, but I'd be surprised if it differs by more than 2 lines of code. Basically it looks like they borrowed the code directly from MvcContrib and added some of their own stuff on top of it.
The code in codecampserver is the test bed we used to create the MvcContrib source code. We have recently brought on a new committer to the MvcContrib project that is going to focus on this area of the codebase. Also, you are right on about the Mvc2 in Action book. We really followed that approach that is outlined in the book. Also, feel free to email the mvccontrib email list.. We do reply to that list, we do not follow the SO questions as much so keep that in mind.