Not sure what OBA is all about - read the intro on the Office Business Appplication Developer Portal -
The 2007 Microsoft Office system provides a comprehensive set of servers, clients, and tools to make it easier for enterprises, software vendors and developers to build and deploy a new class of business applications called Office Business Applications (OBAs).
OBAs connect Line of Business (LOB) systems with the people that use them through the familiar user interface of Microsoft Office. OBAs enable businesses to extend the Microsoft Office clients and servers into business processes running in LOB applications such as Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), and Supply Chain Management (SCM). This enables enterprises to create new value from existing IT investments by combining them in innovative ways.
Still not satisfied with the available information - definitely take a look at the OBA Solution Framework Index - OBA Blogathon. To get you started there are also some sample solution packs available - and recently some new Reference Application Packs (RAP) were recently released:
- OBA RAP (Reference Application Pack) for Plant Floor Manufacturing Analytics - http://msdn2.microsoft.com/en-us/architecture/bb643797.aspx - This RAP contains a reference solution architecture and application that demonstrate materializing a BI centric OBA that integrates tightly with the Microsoft BI platform (Office and SQL Server) to realize the Analytics value chain of enabling operational monitoring, tactical analysis & decision making, and tactical analysis & decision making, and strategic insight.
- OBA RAP for E-Forms Processing in the Public Sector - http://msdn2.microsoft.com/en-us/architecture/bb643796.aspx - This RAP contains a reference solution architecture and solution that illustrate how an OBA (Office Business Application) can be built to automate and optimize forms processing in a Public Sector organization. The reference solution framework show cased in the RAP is generic and can be adapted to enable end-to-end processing of a number of forms in the public sector