put instructions and examples on the same screen as the search box

button to activate search should be next to the input field, viewable without scrolling

indicate how the results were ranked

highlight the search term in the results list

clearly label results (title tag)

obtain search tool that can index other servers, or recommend that all web sites are housed on the corporate server

For information on what a well-designed search interface should look like, see: Jakob Nielsen's Alertbox column, "Search and You May Find."