Sometimes, you just could not be able to install Eclipse Plugin through Help->Install New Software, then type in the URL, for example, StartExplorer plugin.
This is one of my favorite plugins. The way to do this is simply download the jar file, and drop it into C:\Program Files\eclipse\eclipse3.6.1\plugins folder, then restart Eclipse. That's it.
Sometimes, you need check "Available Softwares sites", make sure the site is not disabled.
