MOSS Faceted Search is a set of web parts that provide intuitive way to refine search results by category (facet). http://facetedsearch.codeplex.com/

The facets (Drill Downs) are implemented using SharePoint API and stored within native SharePoint METADATA store. The solution demonstrates following key features:

• Grouping search results by facet
• Displaying a total number of hits per facet value
• Refining search results by facet value
• Update of the facet menu based on refined search criteria
• Displaying of the search criteria in a Bread Crumbs
• Ability to exclude the chosen facet from the search criteria
• Flexibility of the Faceted search configuration and its consistency with MOSS administration

The summary listed above is straight from the codeplex site… However, anyone who hasn't deployed Ontolica or BA-Insight due to budget restrictions should deploy MOSS Faceted Search…

I will be posting more detailed installation, configuration guides along with more xml / xsl examples…

Between the MOSS Faceted Search and the SharePoint Wildcard search you can pretty much have the same result as the retail products

-Ivan