Additionally, there are some good free graphics programs that have excellent support for CHARMM files. One example is VMD, which is free for academia (it's just bad at recognizing CHARMM file extensions so you have to tell it explicitly that you're reading CHARMM files).
These programs won't help you setting up simulations, however. For some common "standard" types of simulations, charmm-gui.org goes a long way. For less standard stuff, there are online tutorials, there's the documentation, and there's the script archive on this site, but it's a harsh learning curve.
Finally, if you have the money, you can also obtain Discovery Studio & CHARMM from Accelrys, which gives you a full Graphical User Interface.