What software is compatible?

[IslandJordan]

Yeah, so I'm kinda new at this whole Unix thing and I really don't understand the whole Cocoa/Carbon/Darwin thing. I am pretty proficient in the Mac OS, but this new Unix thing is throwing me off! I went and got the Unix for Dummies book and I have been entering simple commands to decompress stuff in the Terminal window. Here's my question:

What files will Mac OS X run? I am trying to find a "carbonized" version of Netscape and there is a Linux version of the new Netscape. Will that work? I have downloaded it and I cannot get it to open. The extension is .cgi for the file, how do I decompress that?

Also, I tried to open Outlook Express in OS X... it shows the icon in the dock (without Classic opening!!) but I cannot click on it, or, I should say, when I click on it, nothing happens.

What is going on?
Thanks for helping,

Jordan