As this chapter has shown you, Radio is a very sophisticated product that this chapter only begins to address. The following lists suggests additional online resources.
http://groups.yahoo.com/group/radio-dev/
http://radio.userland.com/directory/6742/developers/
http://ruminations.weblogger.com/directory/143/
http://rcs.userland.com
http://www.soapware.org
APIs, formats, and protocols supported by Radio include:
http://backend.userland.com/rss092/
http://www.opml.org
http://www.xml-rpc.com
http://plant.blogger.com/api/index.html
http://www.xmlrpc.com/metaWeblogApi/
http://www.soapware.org/xmlStorageSystem/