It just so happens that I've set about bootstrapping my development environment within Mac OS X Mountain Lion (10.8).
I first set about Googling for blog entries on the subject and these stood out:
- http://robots.thoughtbot.com/post/27985816073/the-hitchhikers-guide-to-riding-a-mountain-lion
- http://squarism.com/2012/07/27/1589/
- https://gist.github.com/1860902
- http://dean.io/posts/setting-up-a-ruby-on-rails-development-environment-on-mountain-lion
...but stumbled across a fantastic gem by Thoughtbot, a project on Github called laptop which I've modified in my own zsh script
You can find all my tweaks here: https://github.com/bsodmike/laptop/blob/bsodmike/mac