How do you do system integration? | I curious to how different people solve integration of systems. I have a feeling that the last years more and more work has gone into integrating systems and that this kind of work need will increase as well.


I wondering if you solve it developing your own small services that are then connected or if you use some sort of product (WebSphere, BizTalk, [Mule](http://mule.mulesource.org/display/MULE/Home) etc). I'd also think it'd be interesting to know how these kind of solutions are managed and maintained (how do you solve security, instrumentation etc, etc), what kind of problems have you experienced with your solution and so on.