SIMILE, a joint project between HP, MIT Libraries and the W3C, is investigating applying Semantic Web tools, such as RDF (Resource Definition Framework) and associated schema languages, to the problem of dealing with heterogeneous metadata. Currently creating schemas involves writing them by hand using a text editor. As one of the aims of SIMILE is to simplify the deployment of heterogeneous data, it is desirable to investigate the applicability of schema authoring tools that reduce the need for expert knowledge and the risk of schema errors. This report reviews existing applications that support the creation of metadata schemas and graphical user interfaces for entering instance data based on those definitions. It also compares and contrasts these applications with existing applications used for the creation of thesauri, which have many similarities with schemas and ontologies. Notes: John Gilbert, Trinity College Dublin, Dublin, Eire. 25 Pages