Windows 7月7日电话:连接到Web服务 [^ ]应该可以帮助您入门.
WP7连接到XML Web服务 [ ^ ]描述了如何连接到现有的Web服务.
Windows Phone 7数据访问策略:Web服务
[ ^ ]讨论了许多连接到Web服务的策略.

Windows Phone 7 in 7: Connecting to Web Services[^] should help you get started.
WP7 Connect to XML Web Service[^] describes how to connect to an existing web service.
Windows Phone 7 Data Access Strategies: Web Services
[^] discusses a number of strategies to connect to a web service.