The starting point for all things Zope is http://www.zope.org/. This site is not the home of the Zope Corporation (http://www.zope.com/); it's "The Web Site for the Zope Community," so says its tagline . Arguably the most important section of the Zope site is the Documentation section, which is as comprehensive and well written as the application server itself. You can start to see the community aspect come into play: Users can leave comments within the documentation to improve and clarify elements.
These are other very good community-based sites:
Zope Documentation Project, at http://zdp.zope.org/
ZopeZen, at http://www.zopezen.org/
ZopeLabs, at http://www.zopelabs.com/
ZopeNewbies, at http://www.zopenewbies.net/
ZopeWiki, at http://zopewiki.org/ZopeWiki
Invariably, all of these sites have links to their own preferred informational sites, so a little exploring will garner a ton of additional information.
There's also the Zope Magazine, at http://www.zopemag.com/, as well as more Zope- related mailing lists than you can shake a stick at, at http://www.zope.org/Resources/MailingLists.
If you like your information in book form, there are plenty of good Zope books out there, such as The Zope Book , by Amos Latteier and Michael Pellatier (Pearson Education, 2001); The Zope Bible , by Michael Bernstein (John Wiley & Sons, 2002); and The Book of Zope , by Casey Duncan (ed.) (No Starch Press, 2001). As you can tell by their names , they're rather comprehensive and, no doubt, extremely thick.