7-Zip is open source software. Most of the source code is under the GNU LGPL license. The unRAR code is under a mixed license: GNU LGPL + unRAR restrictions. Check license information here: 7-Zip license.

You can use 7-Zip on any computer, including a computer in a commercial organization. You don't need to register or pay for 7-Zip.

The main features of 7-Zip

High compression ratio in 7z format with LZMA and LZMA2 compression
Supported formats:
Packing / unpacking: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM
Unpacking only: ARJ, CAB, CHM, CPIO, CramFS, DEB, DMG, FAT, HFS, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, RAR, RPM, SquashFS, UDF, VHD, WIM, XAR and Z.
For ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip
Strong AES-256 encryption in 7z and ZIP formats
Self-extracting capability for 7z format
Integration with Windows Shell
Powerful File Manager
Powerful command line version
Plugin for FAR Manager
Localizations for 79 languages

Win7 x32, Win7 x64, WinVista, WinVista x64, WinXP

single file, reduce swf file size, 7zip, flash optimizer mac, access compact, zip utility, programm, filtering, 7z files, compress files, backup, repair zip, peazip, split files, backup set, extract rar files, extract zipx, free archiver, optimize flash file, processing, 7zip, ace, access shrink, mac swf optimizer, single executable, 7z recovery