SharpZipLib is a OpenSource .NET compression library that supports Zip files using both stored and deflate compression methods .
The SharpZipLib currently supports the following versions of .NET
- .NET 1.1
- .NET 2.0
- .NET 3.5
- .NET 4.0
- .NET Compact Framework 1.0
- .NET Compact Framework 2.0
You can download the Assemblies here
Know more about SharpZipLib here
There is also an silverlight version of SharpZipLib which can be used with Silverlight 3 , Silverlight 4 and Windows Phone 7 .
Know more about Silverlight SharpZipLib in the codeplex site