The default people search in MOSS refines search results based on Department and JobTitle. When a profile property is created it gets automatically added into the Managed Properties collection. If you need to refine people search by additional profile properties then we need to ensure the following
a) A Profile property needs to be converted to a Managed property. If it is not already present you need to add a new managed property. In our example I have a new profile property called CreditCardType which has its own Managed Property under search setting with the same name CreditCardType.
b) Open the PeopleSearchResult.aspx in SharePoint Designer. This will appear under the master page gallery of your site. Look for <SearchWC:RefineSearchResults and you can add your own entry below the entries for Department and JobTitle <SEARCHWC:RefineSearchResults runat="server" Title="Refine by Card" SearchProperty="CreditCardType"/>
c) Next edit the people Search Core WebPart in peopleresult.aspx in Browser and add the following text in the Selected Columns Property ( under "Result Query Options" ).
The last step is important, without which the refine by link will not appear.