FFSJ-Lite
(ver 3.3)
Abandoned Freeware


"The Fastest File Splitter and Joiner - Lite" 
is a single executable file.  You can use it 
to split files into equal sized parts (or 
after a selected amount of kilobytes), and  
then later join the files together again.  
It can also generate an MD5 Checksum and 
encrypt the split files.  

Although you could use an archiver to split 
files, this is a more elegant solution, and 
one that doesn't require the recipient to 
install an archiver (you can just give the  
Windows user a copy of FFSJ-Lite).