Links:

Welcome to esc3 DOT ORG ...

Another CMS that is gathering popularity with the Education community and the globe ... currently rated #2 at OpenSource CMS:
http://www.opensourcecms.com/index.php?option=content&task=view&id=388&Itemid=143
(OpenSource CMS, BTW, runs a Mambo!)

EDUCAUSE Migrates to Drupal http://connect.educause.edu/

There's a specific distribution for education: http://drupaled.org/

Base: http://drupal.org/

: there are bunches and many I've not found in Mambo (doesn't mean they don't exist in Mambo!). http://drupal.org/project/Modules

: similar to "templates" in Mambo. http://drupal.org/project/Themes

Handbooks: documentation for Drupal http://drupal.org/handbooks

System requirements: http://drupal.org/node/270

Features: http://drupal.org/handbook/modules
One item of difference from base Mambo, users in Drupal are under a roles based system - much finer control that when Mambo currently offers.

Here's something related ... Drupal is being used in the development of something called CivicSpace.
"CivicSpace is a free open-source software platform for grassroots organizing and civic activity. It allows individuals and organizations to build online communities that communicate effectively, act collectively, and coordinate coherently with a network of other related organizations and communities."
http://civicspacelabs.org/home/download