The Javalobby has a great article called Eclipse: Managing Multiple Eclipse Installations that shows you how you can keep one plugins directory and have it work for multiple eclipse installs.

Since I do a lot of Java 1.5 development, I have to use Eclipse 3.

I just tried out an eclipse plugin for spell checking. It works with the CFEclipse plugin, Java, JavaScript, JavaProperties, XML, HTML, JSP, and PHP.

While the dictionary could use some work, the plugin is pretty good.

Just download it and unzip to your eclipse directory.