VERY simple tool to adjust the search relevancy settings in MOSS 2007 and the Microsoft Search Server. Originally published and available on SHAREPOINTSearch.com.
This tool will allow you to change the weighting and normalization of Managed properties and some of the system level relevancy settings also! Easy to use, no code to write.
Run this tool on a machine that has SharePoint installed so that it has access to the libraries. Be sure that the user you run it as has permission to modify the Search Schema.
More information on search relevancy and sharepoint here: http://msdn.microsoft.com/en-us/library/ms584432.aspx