I have just installed Android Studio 0.2.2. I want to add the SDK tools to the $PATH, which are in this folder:
/Applications/Android\\ Studio.a
You can add this folder to you PATH in .bash_profile (a hidden file in the home folder of the user):
export PATH=/Applications/Android\ Studio.app/sdk/tools:$PATH
and then reopen the terminal application.
If you need an environment for all your UI apps, you can use the .launchd.conf (or /etc/launchd.conf for all the users).