IronRuby Getting Started Links
Justin Etheredge wrote a detailed step-by-step blog post about how to download, build and get IronRuby up and running which is really good.
There is also the new wiki on the official IronRuby web site (www.ironruby.com) which covers the same topic and also has a few code samples that might get you going a few steps further - look at the FAQ pages.