Cygwin

A great free tool suite that contains many of the commandline tools available in a standard linux/unix installation such as grep (for pulling specific patterns out of text files) or C/C++/Fortran compilers which are useful if you find yourself using Glen Liston's MicroMet among other programs. Or, perhaps you'd like to run your own program written in Fortran on windows. Either way this is a great program and you can find it here:

• Cygwin Website