HJ-Split (Freeware file splitter for a variety of platforms)
Why split files? Think of a file of 20 Mb, and try to send this to a friend. Using email this does not succeed, it is simply too large, and how to put it onto a floppy? HJSplit will enable you to split the large file into smaller chunks, which can be much more easily sent and stored. Later on these chunks can be re-joined using HJSplit itself or HJJoin.
HJSplit is available for a large number of operating systems:Windows 95/98/NT/2000/XP, Linux, Java, OS/2, Windows 3.x, MS DOS, Amiga. For the MAC there is a compatible file joiner available.
Freebyte ZIP
A powerful freeware ZIP program with full Windows user-interface. It can zip and unzip files, create new zip files, directly view and sort zip file contents, make self-extracting archives, password protect and encrypt files, etc. etc. Runs on windows 95, 98, ME, 2000, NT and XP.
StuffIt
Mac file expander (program to open compressed files) for the MAC platform. Support for various file formats, like BinHex, MacBinary, zip, gzip, uu, tar. Lite version is freeware.