A while ago I wrote an article titled Taking part in a System.Transactions transaction, with some details on how to create your own class that takes part in a transaction, instead of just using the standard functionality.

Now Sahil Malik has posted a new article that's certainly worth a read because it contains information on recent changes in VS .NET 2005 beta 2 (I haven't found the time yet to look into these changes myself) and another practical example of implementing one's own transaction participant. Go read it!