To Install JRuby:

Download JRuby from http://code.google.com/p/schnell-jruby/. Best is to use JRuby 1.1.2RC2 or later. You can download JRuby compiled version and unzip it any of folder. If you wish to use JRuby from the command line don't forget to add it to the path.

To install HtmlUnit:

Download HtmlUnit from http://htmlunit.sourceforge.net/. Best is to use HtmlUnit 2.1 or later. Place all the HtmlUnit jar files in class path or simpler copy them all to the JRuby /lib/ruby/1.8 folder.

To Install schnell:

Best way to install is to use the gem. You can download the gem from downloads page either as gem or source

From your command line:

> gem install schnell

This will install schnell. You can use it in your code now by requiring schnell. If you use the source unzip it somewhere where JRuby can access it.