You can use Dotfuscator. A community edition ships with VS2008 and later or you can purchase a version that does more.

>Hi There
>
>Were developing a comercial grade application.
>
>I understand that C# and VB.net code is fairly easy to reverse engineer from the Microsoft Intermediate Language and Metadata contained in assemblies.
>
>Is it possible to get as close as possible to 100% source code protection using Obfuscation and any other techniques ?
>What are the best techniques to ensure source code protection.
>
>TIA