I'm trying to list the existing WO sites below from my bookmark list. This should ensure no new efforts are duplicated with existing efforts/content.

Maybe there could be some consolidation of sites, but I guess that's up for each site owner.
James (Wocode.com) already proposed opening his site to others on the list: http://lists.apple.com/archives/webobjects-dev/2006/Aug/msg00645.html

Please also see an extensive link list here:
Additional Resources-Websites and here http://en.wikipedia.org/wiki/WebObjects

Code and Frameworks

Apollo
https://sourceforge.net/projects/apollo-project/

Community

Mac / WO Developer directory
http://mdd.gebe.net/cgi-bin/WebObjects/MDD.woa/
-> checkbox for WO in Search mask