Downloads from empublic are in .tar.gz format. This is a compressed tar file. Tar is the "tape archive" format, which is simply a way of concatenating multiple files and directories together into one file. The compression scheme used here is gzip.

A gzipped "tarball" can be extracted quite easily on most platforms.

Windows

Obtain a copy of winzip from www.winzip.com if you do not already have one, and use that.

UNIX

Uncompress the file first using gunzip filename.tgz. Then have a look at the names of the files included in the tarball by using tar tvf filename.tar (make sure it won't overwrite anything critical!). Finally, extract the files by using tar xvf filename.tar.

If you are feeling confident and have the GNU tar (which may be installed as gtar on systems or just the plain tar on some others), the file can be uncompressed and untarred with one command: use tar xvzf filename.tgz.

Mac OS

StuffIt should be able to handle this format.