From: DeskNow Knowledge Base
http://www.desknow.com/kb/

How do I sync with my iPhone?
http://www.desknow.com/kb/idx/17/187/article/

You can sync your iPhone with your DeskNow account by using the iPhone SyncML client. We recommend the one available from Synthesis: http://www.synthesis.ch/

Once installed the client, simply follow the usual steps as for other Synthesis SyncML clients, eg. http://www.desknow.com/kb/idx/0/125/article/

Please note that the SyncML functionality requires a SyncML Connector license to be present on the server - the functionality is also enabled during the initial 30 days trial period. For more information, see http://www.desknow.com/syncml/buy.html . The SyncML Connector license lets you and your users not only sync with iPhone devices, but also with Outlook and most other mobile phones and PDAs, including Windows Mobile, BlackBerry and Palm.