Upgrade
Upgrading SIDE-Labs means upgrading SIDE-Labs Plugins only. You don't need to download the whole package!
You can upgrade your SIDE-Labs installation either through Eclipse update site or binary distribution.
Binary distribution
Download the last version of SIDE-Labs plugins in the following directory. Locate the SIDE-Labs-Plugins-2.0.xx.tgz where xx is the bigger number you can find.
This binary distribution is OS independent, so you can download it for Win32, Mac OS X, ...
Once downloaded, locate dropins directory in your eclipse installation and copy the features and plugins directory of your just downloaded distribution into it. That's all. Be careful to not copy site.xml in this process.
Stop then restart Eclipse.
Eclipse Update Site
The eclipse update site is not available for the moment. It should be accessible soon (end of october 2009)