Yesterday LambdaUX and Imendio finally release the first version of the OpenGroupware.org GroupDAV Evolution connector. It has been developed in the project Noodle and we started developing it around 23 November and this was the roadmap for it. Anders from Imendio invest some intensive hacking time in the connector to finally deliver a very nice first version (for the time and limitations he has found) whith the results that you can see in this screenshots tutorial (1 MB). You can also take a look to Anders final report. Finally, the connector is a GroupDAV connector, so if your GroupWare server implements GroupDAV, it could be a cake to connect Evolution to it.
Helge Hess, from OpenGroupware.org, has helped us a lot. Now thinking about the future, Anders and me aren't sure about how many time we will have to mantain the connector and finish it, but we will try to help. For mainstream, we need to wait first to Evolution 2.2 release before we can start pushing the software in distributions.
I hope I can get some of the code developed, for example the account creation (camel provider and EPlugin), for the Evolution Planner backend. Noodle project also includes the integration with Evolution for the PDA world. The time for Planner<->OpenGroupware<->Evolution<->PDA is near today.