I installed pod some time ago. However, it\'s stopped working so I\'m working through this again.
However, I almost immediately run into a problem here:
I had the same problem, running Mountain Lion with Ruby 2 installed and used instead of system ruby.
Previously I added PATH=/usr/local/bin:$PATH to my ~/.bash_profile as a way to make sure stuff installed by homebrew, including Ruby 2, took precedence over system-installed binaries.
Anyway, in this case I noticed that cocoapods would install their 'pod' binary not in /usr/local/bin but rather in /usr/local/Cellar/ruby/2.0.0-p247/bin/
So to my .bash_profile I added PATH=$PATH:/usr/local/Cellar/ruby/2.0.0-p247/bin/
and now cocoapods is working like a charm.