There's no direct way to upgrade an installation of 3.1 to 3.2 - but you
can move your workspace(s) to 3.2, and that contains most of your
settings and preferences. The recommended upgrade path is to download
and install 3.2 into a clean new directory, then install your additional
plug-ins on top of that, then launch eclipse pointing to your old
workspace. It's also a good idea to backup your workspace before doing
this in case you need to go back to 3.1.