Paul Thurrott's SuperSite for Windows takes a look at cloud-based data sources for the upcoming Windows Phone 7

Windows Phone will only sync with cloud-based data sources like Exchange, Windows Live, and Google/Gmail, so those who are still using Outlook as a hub for their personal information are going to have to move their data to the cloud. This isn't a bad thing. In fact, it's an opportunity to jump into the 21st century and make your data more resilient and accessible.

  Windows Phone and the Move to the Cloud