installing RubyMine on Ubuntu 8.10

Jason,

Often you can stuff an environment variable in your own space that
defines what you need.

i.e. in ksh or sh (and maybe bash)

export JDK_HOME=/full/path/to/jdk

Check the RubyMine install instructions. Also, if you're just
evaluating you might check out Sun's NetBeans. It's a fairly mature
IDE with an active development community behind it.

Rick