7-ZIP
http://www.7-zip.org/
7-Zip is a compression software with the highest compression ratio of the world.
7-Zip is a file archiver with the highest compression ratio. The Program Supports 7z, ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM AND DEB FORMATS. Compression Ratio In The New 7z Format IS 30-50 % better Than Ratio in Zip Format.
http://www.hyzgame.org/links/freelib.htm
