Alex,
You can install on one machine, under a common root, something like this:
c:\dev\MyEclipse
\eclipse-3.0.1\ unzip Eclipse 3.0.1 into here
\myeclipse-3.8.3\ install MyEclipse into here, using the manual installer or the double-click one
\workspace your workspace directory (empty at first)
Run the instance and specify a workspace location of: c:\dev\MyEclipse\workspace. Once running, switch to the MyEclipse Perspective and enter the license key for your group (assuming a single group key). Shutdown Eclipse.
Now you can zip c:\dev\MyEclipse and simply unzip to all the machines.