Faceted Search

New project at codeplex which searches as per category ...
http://www.codeplex.com/FacetedSearch
Some of the advantages listed are

1) Grouping search results by facet
2) Displaying a total number of hits per facet value
3) Refining search results by facet value

Project to customize the small search control in SharePoint 2007

This control is actually available through a feature called "OSearchBasicFeature" located under 12\TEMPLATE\FEATURES. In the feature elements file (in this feature it's called "SearchArea.xml"), you can see the following

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Wildcard Search in SharePoint

doesnot come out of box here is a way