It was published along with guidelines for the design of RSS Modules so that RSS can be easily extended.
The URI http://purl.org/rss/1.0/modules/ can be used to represent the class of RSS modules.
The following modules are official modules of the RSS-DEV working group:
RSS has an RDF Schema available. A copy is also embedded in this document.
Leigh Dodds has created a Schematron Schema for RSS 1.0
Development and discussion of RSS takes place on the RSS-DEV Mailing List. Feel free to email the list with any questions regarding RSS that you may have.
The following sites also provide more information on RSS:
Use of the RSS CSS Stylesheet will help the specification display properly.