We have a Funambol connector which was written for ZCS v3.1 and Funambol v2.0. Our hope would be to put this in our zimbra-xtras SVN and get a few interested parties work on updating it to the latest version of Zimbra (v4.5.x) and Funambol (v3.0 and v6.0 beta). Keep an eye on this thread as we work to get the code in SVN and grant SVN commit access. As a start if your interested in helping and don't already have a signed contributor agreement please sign a copy and fax/mail a hard copy to us.
http://www.zimbra.com/community/contribute.html