GemJack: Online HTML documentation for all gems
GemJack.com is a basic, but highly effective, site featuring full HTML documentation for most of the Ruby gems (Ruby's library packaging system). Hopefully it'll get indexed by Google in full and beginners will find it easier to find the documentation they want straight from Google.
One alternative, however, is to run gem_server on your local machine, whereupon all your installed gems' documentation will be available at http://localhost:8808/ . If your gems don't have documentation pre-built, you can build it with gem rdoc -all