Search (such as those of Live Search and Google) is so ambiguous now that users would have start asking it especially if your system spans a few terabytes where searching for information is tedious. Within OBA architecture is the Search services which is powered by SharePoint Search and BDC, basically what you need to do are:

1. Create a DBA Application Definition XML with IEnumertor and Specific Finder method instance.
2. Define the BDC app as Content Source
3. Setup Authentication
4. Perform a content crawl
5. Setup metadata properties and crawled property
6. Create Search Scope
7. Publish the scope to site
8. Create a search web page

So it is that simple, more details you can get it from winsmarts website here.