PIP your AIA

AIA stands for Application Integration Architecture. Architecture (http://dictionary.reference.com/browse/Architecture) is a fundamental underlying design of computer hardware, software, or both. In other words, it is an integrated set of tools and concepts which helps you build new solutions. All major software vendors have their own AIA delivered via the Application Servers, JBoss from RedHat, WebSphere from IBM, Oracle 10g AS from Oracle, WebLogic from BEA, NetWeaver from SAP, WebMethods. If you look into each of the AIA from each of the vendor, you will not see much difference in terms of delivered functionality. Each architecture includes an HTTP Server, a servlet container, an Enterprise Service Bus, a BPEL Engine, etc.

What does differentiate one AIA from another? PIPs, the Process Integration Pack.

PIPs are pre-built solutions for specific tasks. For example, if your company is implementing Oracle Siebel CRM and Oracle eBusiness Suite Order Management, you go with Oracle AIA and use Siebel CRM Integration Pack for Oracle Order Management. Surely, both WebSphere and WebLogic have Oracle eBS and Siebel adapters, and one can build a custom integration solution with AIA from IBM or BEA. However, only Oracle AIA with the PIP gives you the initial boost. When you implement SAP and integrate it with Siebel, your best solution would be the SAP NetWeaver for the very same reason. You use AIA from 'independent' vendors like IBM, BEA or RedHat when you need to integrate multiple applications with and there are no PIPs available. For example, if you are integrating Oracle eBusiness Suite Financials with Lawson Financials, your best choice would be WebSphere because there are already adapters for both of the applications available with no PIP to boost your integration.
Resume: before committing to an AIA from a vendor, investigate what PIPs are available for the integration which you need to build. It may be better to change the AIA in order to unitlize existing PIPs.