The jEdit Ruby Editor Plugin lets you manipulate Ruby and Rails code at the syntax level. Focused on programmer productivity, the plugin provides method completion and an integrated Ruby documentation viewer.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
Major new features include method completion for
Ruby's core types and an integrated Ruby
documentation viewer. A few bugfixes have been
made to the Ruby parsing code.