Get Google Voice support for Windows Phone 7. The app allows you to make cheap long-distance calls, send and receive SMS messages, and even access transcribed voicemail. Though domestic calls will cost you (using your plan's minutes), international calls are charged at Google's cheaper rates and messaging is free.
WIRED Quickly pull up your phone's contacts. Separate screens for inbox, voicemails, and texts.
TIRED Requires frequent refreshing and crashes often.