heh bean!I use a Mac too... ok for RAR,u gotta use RAR for Macs... try these...
www.rarlab.com/download.htm
fileforum.betanews.com/detail/1053350629/1
Usually they will comes a command line type of program, i.e. you have to use Terminal.
Hence you should open up a terminal window and drag in the file (which brings up the command in the window).
after that, you can try to meddle around with the various modifiers/commands etc. that are available. The format is:
rar <command> -<switch 1> -<switch N> <archive> <files...> <@listfiles...> <path_to_extract\>
i usually use the following:
..../rar e <archive to be extracted> <directory to extract to>
Hope it helps! if you need further help just drop me a mail or something...