You can have a search server that is not your Web server, but it must host the
IndexQuery role as those cannot be seperated, as Brian said. that's about the
extent of farm scaling with WSS. You probably don't need multiple WSS search
servers as it uses the change log for incremental indexing and is *usually* very
efficient. Also beware that content databases are associated with WSS search,
whereas MOSS search associates URLs. These are detailed in the ms press
sharepoint pocket consultant.