I want to share the output from my little personal project with you.
The project's goal is to make Zimbra Server "OAuth"able, which means you can use it as OAuth provider by the output.
Thanks to the Java OAuth library(oauth - Revision 1143: /code/java), i have got some Zimbra Extension working.
Before deployment, please read through the README.txt file,
which describes requirement, deployment step and limitation
I am very happy to have your feedback, your question and some discussion with you.
NOTE:This extension is tested only on 6.0.1_GA_1816.MACOSXx86_10.5 FOSS edition with OAuth signpost(oauth-signpost - Project Hosting on Google Code)