Microsoft has released a paper that describes how to build Windows Phone 7 applications with SharePoint 2010 Products and UAG.
This white paper describes how to build Windows Phone 7 applications with SharePoint 2010 Products and Microsoft Forefront Unified Access Gateway (UAG). It provides business scenarios that can benefit from custom mobile applications that authenticate by using UAG and use the features of SharePoint for collaboration, and introduces the concepts and code that are required to access SharePoint list data in a secure manner from a Windows Phone 7 device.Building Windows Phone 7 apps with SharePoint and UAG