I don't have the URL handy at the moment, but Expeditious Retreat Press offers a free chapter from one of their books entitled "A Magical Society: Guide to Mapping." Search the forums for that, and you should find a link to take you to a place where you can download it. It gives some decent guidelines on climate and mountain placement.

Also, for mountains, try searching the forums for the word "tectonic." You should come up with some threads where those forces are discussed. (In great and sometimes correct detail. Thanks for the chuckle, Joe.)