Gnutella Forums - Trying to download a program

I am confused, I want to download a fairly large program, several hundred MB, off of Limewire. When I type in the name of the progarm, learn to read then maybe you will not break the simple rules of this forum, I get back choices which are .zip files from 110kb to 770Kb in size, there are also .exe files of similar size. My question is how can I get the real program because I am assuming there is no way even a .zip file of that size could be a program which is a couple of hundred MB. Is there something I am missing? How big should a .zip be to equate to say 200MB. Also, should I always be looking for one with a "crack" . What does it mean when I see these downloads that say with crack?
Also, what is an .iso file

Thanks for all the help.

http://www.gnutellaforums.com/images/misc/progress.gif http://www.gnutellaforums.com/images/buttons/edit.gif