Maemo5 does not support SyncML out of the box. SyncML is a standard used to synchronize clients with a SyncML server. There are open source server software (like Funambol provides) and a lot of clients for nearly every plattform as you can see here. The idea is to have also a solution to synchronize Contacts, calendar entries, tasks and notes (and maybe more stuff) from the N900 (Maemo5) to a SyncML server.

Services (free and paid) offering SyncML can be found here.

The first idea to solve this is to use syncevolution. Syncevolution runs very well in maemo4 already and maybe it's the easiest way to implement it also on maemo5.

Update (2010-01-28): Ove Kaaven will maintain a version for maemo. See this announcment on syncevolution.org. In this way syncevolution arrived maemo extras-devel repository!

Update (2010-02-10):There also is a nice GUI available for syncevolution. Just install syncevolution frontend from extras-testing.

Vote here (or post other solution ideas): http://maemo.org/community/brainstor...rt_for_maemo5/