The Esendex .Net SDK is an easy to use client for Esendex's REST API which you can use to integrate SMS and Voice messaging into any application built with C#, VB.NET, Managed C++, F# or any other language built on the .NET framework.
It contains a set of services for sending SMS and Voice messages, receiving SMS, tracking the status of your sent messages and more.
Full details at http://developers.esendex.com/SDKs/DotNet-SDK