Download Site:
FreeMat downloads for all platforms are available from the sourceforge website. I found the instructions less than clear but be persistent and it will work. Be careful about operating systems etc etc as usual.
A note for Linux users: I have been told that "As far as freemat goes, anyone using a Debian based distribution (Ubuntu, Mint, Crunchbang, etcetera) can simply type: sudo apt-get install freemat into their terminal to install it. The sourceforge page isn't very good at detecting which package manager one might be using" (thanks Kyle!) will be helpful.