A nice how-to for installing the RadRails plugin into Eclipse for the Ruby on Rails developers
Satish's Blog: installing RadRails on Eclipse ...........
Develop Ruby on Rails Projects with Aptana Radrails
Aptana RadRails contains tools for writing code, tools for testing and debugging, and also tools for project management. Users will also learn how to use other Eclipse plug-ins for synchronizing their projects with Subversion and for managing their databases.