The latest stable packaged version of Zenoss Core, version 2.3.3, is now available for download. Zenoss Core 2.3.3 is available from:
http://www.zenoss.com/download

and the release notes are available here:

Release Notes for Zenoss 2.3.3

Installation and upgrades from earlier versions are now covered in a unified document available here:

Zenoss 2.3 Install Guide (zipped PDF)
OSX instructions (zipped PDF)

This is a maintenance release that addresses the following issues, by release:

Verified defects fixed in Version 2.3.3
Verified defects fixed in Version 2.3.2
Verified defects fixed in Version 2.3.1
Verified defects fixed in Version 2.3.0