I received some questions today on how to display the pdf icons in search results. After you can index pdf documents  (installing the pdf ifilter, bouncing the search service and all that good stuff), please use the instructions on the blog given below to surface the pdf icons in search results. Note that you need to do this on each WFE.

 http://www.sharepointblogs.com/wpowell/archive/2007/08/09/pdf-document-type-icon-in-moss.aspx