Enterprise Application Integration (EAI) has been one of the most complex areas of Enterprise software. Basically it involves integrating anything to anything, whether it's packaged ERP and CRM systems (e.g. SAP, PeopleSoft, Oracle, Siebel, etc.), custom applications, web systems, mainframes, order entry systems, you name it, in real time. It's the type of projects that cost companies millions and take years to do with custom coding and, to be honest, they aren't a lot faster or cheaper when you use some of the commercial offerings from the likes of IBM, webMethods, SeeBeyond, Tibco etc. (Full disclosure: I ran marketing at webMethods a few years back.)
Although its not "mass market" like the database industry or web development tools, there is a strong potential for open source to help lower the threshold in EAI. A few projects, such as OpenAdapter were born from the frustration and mounting costs among financial companies doing custom EAI work.
Now comes word that Celtix, a project from ObjectWeb, based on code from IONA's Artix server, will lead the charge. This is one of several open source integration projects in the waiting.
You can read the full story here on CNet.