Free Compilers (lisp, Ml, Prlog, Etc..)

This thread is to discuss free compiler resources. I will start it by providing the following link I found.

http://www.freeprogrammingresources.com/lispcompiler.html

One of the better C++ compilers/editors can be found here.

It is completely free so if you need a editor and don't want to spend LOTS it is a fairly nice one.

http://www.bloodshed.net/devcpp.html

Obviously the java system:

http://www.oracle.com/technetwork/java/index.html

Not really a compiler but very useful if you want php on you computer:

http://www.easyphp.org/