On my random blog reading and Googling around System.Transactions and Unit Testing, I ran into a series of short but great articles by Stuart Celarier which actually covers both topics. Stuart teaches the reader about System.Transaction by using unit tests in a very educational (and entertaining) way. 

He uses NUnit in his articles, but nothing will stop you from using the test mechanism built into VS.NET if you got that Team Edition version. Just use the [TestMethod] attribute instead of [Test] and all sample code in the articles will compile and test well (eventually :)

Stuart also make use of anonymous methods for testing events that I recently blogged about.

System.Transactions is good stuff, I wonder if it could be useful to manage "compensating transactions" when dealing with multiple web service calls within a transaction?