7-Zip

7-Zip is a file archiver with high compression ratio. The program is fully integrated to Windows Shell, so all archive operations like extracting, compressing and browsing can be executed using usual Windows Explorer. The program supports ZIP, 7z, RAR, CAB, GZIP, BZIP2 and TAR formats and for ZIP format it provides compression ratio that is 2-10 % better than ratio provided by any other zip compatible compression tools, like PKZip and WinZip. There is also additional powerful command line version of program for backup and other purposes.
Platforms supported:
Windows 95, Windows NT, Windows 2000, Windows XP, Windows 98, Windows ME, Windows Server 2003, Windows XP x64, Windows Server 2003 x64, Windows Vista