The device bits for Sync Services for ADO.NET have been released to the web so now we have a have a supported version of Sync Services for Windows Mobile 5.0 and 6.x. You can find the download at http://www.microsoft.com/downloads/details.aspx?familyid=75FEF59F-1B5E-49BC-A21A-9EF4F34DE6FC&displaylang=en