If you want to install JBoss Tools plugin (or some part of it like Hibernate Tools), just google "jboss tools download" and you will get to this site: http://www.jboss.org/tools/download On this web site there are stable releases, development milestones and nightly builds. Most users want to download either stable releases or development milestones.
Just be sure to download right version for your Eclipse IDE. Currently latest Eclipse version is Indigo, which is 3.7. In order to install these plugins, drag and drop this install button to your Eclipse somewhere up here. This will trigger installation process.