To bring the library catalog and other online resources right into users' workspace quickly and easily without needing much more than a short XML file, the author, a reference and Web services librarian at Williams College, learned to build and use OpenSearch plug-ins. OpenSearch is a set of simple technologies and standards that allows the sharing of search results. It was developed by A9.com, a subsidiary of Amazon.com. Part of OpenSearch is the OpenSearch description document, an XML file that describes a search engine. It allows other programs (like Web browsers) to integrate elements of that search engine into their interface. Here, the author describes how to create an OpenSearch plug-in for the library. (Contains 4 online resources.)