how to find and install fortran 90 in Redhat

One of my software should be compiled by fortran 90 under liunx enviroment. I have installed Redhat 7.2, but I don't know where is the free software of fortran 90.

Is there anyone have this kind of knowlege?

Thank you!:confused:

You may find this page useful: http://www.nikhef.nl/~templon/fortran.html