Microsoft My Phone syncs information between your mobile phone and the web, enabling you to:
  • Back up and restore your phone's information to a password-protected web site
  • Access and update your contacts and appointments through your web account
  • Share photos on your phone with family and friends

* Works only on Windows Mobile 6+
* The service is free!
* Provides 200 MB of free storage
* Can backup data automatically
* It's a Cloud (web based) service.

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Use it now!

I don't have Window Mobile so I can't test it now. These screenshots are from web.