Sax.net Streaming Compression helps you keep your data small and fast. Use high-performance compression and data compression code, using a class library that was designed from the ground up for integration with the Microsoft .NET framework.

In addition to being able to specify whether to prefer speed over size, Sax.net Compression offers you a choice of two compression algorithms: Industry-standard Deflate (ZIP) compression, and the newer Burrows-Wheeler (BZip2) transform, which generates especially great results when compressing XML data.

http://www.sax.net/dotnet/compression/