This link explains the unit testing tools available in VS.NET 2008 Professional. My take after reading that section is that Microsoft doesn't get it. Here is my list of observations about this section. Feel free to leave a comment to tell me where I'm wrong.

• I feel like this is nothing more than an upsell to get me to go and buy VS.NET TeamSystem. Sorry, that's not going to happen. TeamSystem is way too expensive (both initially and in setup/maintenance time for a TFS server). Besides, we have an existing development infrastructure setup since we use multiple (non-MS) languages/platforms here.
• It looks like MS wants to ignore the thriving and long-standing community of open source unit testing tools. I'm willing to bet that NUnit (and MbUnit, etc.) has more code using it than Microsoft.VisualStudio.TestTools.UnitTesting. Yet, if I want to use the integrated Test menu in VS.NET, I need to rewrite my unit test code to use near-identical attributes for my unit tests (e.g. [TestMethod()] vs. [Test]).
• Code coverage is not available in VS.NET Pro. I guess code coverage isn't something that developers should be doing - well, unless they shell out tons of money to get it done. Thankfully, there are free alternatives, with cheap upgrades to the latest version.
• I want to easily run and debug my unit tests. I know Resharper can do this, but I haven't installed that in VS.NET 2008 due to the number of issues I had with it. (Yes, I know an EAP is coming out soon, but I also have CodeRush and Refactor, which work fine with 2008.) I like TestDriven.net,  but I'd like to be sure that it doesn't go away.
• The documentation is too cluttered. If you're going to give me a list of what's included and what's not included in the Pro version, then why not just separate the documentation to make it easier for me to see what capabilities I have (and what I don't).

In short, it's disappointing that MS has chosen to force people to one specific way of writing unit tests that is against industry norms. ASP.NET has shown me that they do understand the provider model, so why not use it here to allow me to run and debug my unit tests using whatever tools I want.