As far as I know Ovi is using SyncML via HTTP. My Nokia E51 is doing SyncML via HTTP and syncs nicely to Funambol.

Also I think that Maemo5 is doing SyncML via bluetooth using Funambol libraries for connecting to the desktop software. Those libraries are used with a commercial license, though.

Further I think that (in principal) those libs shouldn't have any problems doing SyncML/HTTP. So to me it looks like the best two options are:
* Hoping that Nokia will add SyncML/HTTP
* Investigate the Funambol libraries further and try to get HTTP support hacked in