[Exim] New Exim user question

Hello All,

    I am looking at Exim to replace my current Smail 3.2.0.107 on an AIX
4.3.2 server.  Are there any caveats about running Exim on AIX?  Also,
I am new fairly new to UNIX and can't figure out how to successfully
unpack the exim-3.13.tar.gz file.  If I use gunzip,  it unpacks it to a
file named exim.tar-t.  What am I doing wrong here?
Sorry for the bonehead questions.
Thanks,

Tim Sexton
Younglife
Network Systems Eng.
CNE