If you're doing sophisticated business process management or if you want to implement B2B successfully across multiple organizations, you need a very robust messaging infrastructure such as IBM's MQ Series or Tibco's ActiveExchange or ActiveEnterprise. In Europe, Software AG's EntireX is very popular. Some messaging products are folded into more complete application integration solutions where you can do both messaging and data transformation. Middleware can be expensive, and not everybody's skilled at working with infrastructure products. Implementing MOM takes thought - you have to have some systems architecture design up front.
Training internally is a good idea.
Once it's up and running, it's okay. But it's not something you can buy off the shelf and snap in. To figure out how heavy or lightweight a solution you need, you need to have a good idea of what applications are in your enterprise and what's going to be added to your enterprise through acquisition or collaborative working arrangements. Take a look at some of the past winning tips in the searchWin2000 hall of fame. Living up to its promises 2.