orcishgamer: POM files are object models for a project, they can inherit from one another and do all the things that you would expect when you hear "object model". I typically create a parent POM and then inherit from them for each sub project (domain, dao, etc.). Usually each POM will produce an artifact during build, but it doesn't have to.
Now, at first glance it's easy to think, "Maven, yeah, another build tool, so what?" And Maven does do builds, but since it's a project description you can do any number of things with it (and the appropriate plugin) such as create a website for your project, complete with Javadocs and unit test coverage. That's the power of a project description over a straight build file (like Ant or Nant). I'm probably not doing it justice, honestly.
I thing MSBuild goes beyond a simple build tool as well, but I don't have more than very limited experience with it, and that was a couple years ago. MSBuild, from what I recall, allows inheritance or properties and allows you to call external programs/plugins, etc.
The .NET doc xmls are built depending on project settings, converting them to a webpage wouldn't be too tough, I don't imagine. I do prefer Java's method of sharing code documentation over .NET's, which has to be included in the help application or some such. I like things being separate.