http://www.7-zip.org/ Open source, Free (as in freedom), and free (as in cheap). Also available for Linux/*BSDs and other operating systems. From their website: ⋅ Supported formats: ⋅ Packing/unpacking: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM ⋅ Unpacking only: ARJ, CAB, ...