Are you still using Win Zip to compress/zip files?  And if you are, you're probably like many people using the evaluation, which means NAG screen of annoyance.  Well, you can buy Win Zip, or you can download 7-Zip.  7-Zip allows compression and decompression in 7z, ZIP, GZIP, BZIP2 and TAR and unpacking.only in ARJ, CAB, CHM, CPIO, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z.  This is the last compression utility you'll ever need again.  Oh, and it is very efficient in compressing things, which translates to smaller files.

7-Zip site