Seems topic Enterprise Service Bus (ESB) wasn’t as popular as previous ones at Dublin ALT.NET so there was only 15 people attending. Only 1 person in room had experience with it and few others have heard about it. It seemed pretty complicated and was hard to get my head around it.
Following paragraph is my summary of what I understood from the evening. Please correct me if I’m wrong at some points.
As I understood ESB is message layer that communicates between components within enterprise system. There are asynchronous ESB listening processes that handle each message request and distribute them. It is good for scaling, but ESB integration needs big money investment, constant monitoring and it has large learning curve. This is one of the reasons it’s not usually implemented in small systems / small organisations.
You can read more about ESB at Wikipedia or buy a book about it

Yeah, it was interesting stuff I thought, fairly high level. There was a brief article on CodeProject last month discussing nServiceBus, might be of use too; http://www.codeproject.com/Articles/35147/Open-Source-Integration-with-nServiceBus.aspx
Thanks for info Dave. Looks quite interesting, will look more into it
Just thought i can add some links of interest:
http://www.nservicebus.com/
http://www.udidahan.com
http://www.enterpriseintegrationpatterns.com/
http://www.amazon.com/Enterprise-Integration-Patterns-Designing-Addison-Wesley/dp/0321200683
HTH
Wow, thanks Sean. Really value your feedback guys
This kind of is considered reputable information. Thank you