Chmod Information
When you download a php or cgi script the installation guide often tells you to chmod one or more files or a directory. 666, 755, 777 or something else. To chmod a file is to set permission how the file can be accessed and executed on the server. Below are examples.
666 = Read & write for all three columns
755 = Read, write & execute for owner, read & execute for group & other
777 = Read, write & execute for all.
Here is an example on how to CHMOD to 666 in WS_FTP. Right click on the file or directory you want to chmod, click on "chmod (UNIX)" and select read and write for owner, group and other. It looks pretty much like the calculator below. The procedure is pretty much the same in all FTP clients.
Actually chmod is not used only for websites. If I'm not totally wrong, it's the way of setting permissions on UNIX, Linux, *BSD, etc. machines. If you want to know more about that, do some google searching.