For those of you who need a program that can unzip RAR files as well as ZIP files, there is a free archiver utility called PeaZip.

PeaZip free archiver utility is a portable, open source archiving, encryption and file split tool.

PeaZip is cross platform and runs on 32 and 64 bit Windows (9x, 2000, XP, Vista) and Linux. It supports handling many archive and compression formats:

create: 7Z, ARC, BZ2, GZ, PAQ/LPAQ, PEA, QUAD, TAR, UPX, ZIP;
open: ACE, ARJ, CAB, DEB, ISO, LHA, RAR, RPM and more archive types

Available here