A while ago we had a session on messaging at ALT.NET Belgium and it was then that i decided i should order my copy of Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions. I found first half of the book pretty interesting but got bored around chapter 8 and skipped some sections from there. All in all this book this book is pretty good and if you know a thing or two about TCP/IP implementations you might even recognize some patterns in a different problem space.