Introduction
The functionality of Eclipse can be extended with more plugins and these are often free and sometimes open source. They can usually be installed the same way as you first installed WOLips. Simply get the appropriate update "Update URL" for the plugin (or sometimes a selection of plugins are available from the author), create a remote update site and install. The remote update site URL can usually be found somewhere in the documentation and often is more convenient that downloading the files and installing from HD.
Of course, if you are reading this, it goes without saying that WOLips is the most useful plugin of all! 
Useful Plugins
A word of warning regarding Metrics: it turned my macbook pro from a leopard into a slug. It churns away producing all sorts of nice stuff but I would recommend a serious beast to run it on.