Type sudo vi /etc/launchd.conf (note: this file might not yet exist)
Put contents like the following into the file
# Set environment variables here so they are available globally to all apps
# (and Terminal), including those launched via Spotlight.
# After editing this file run the following command from the terminal to update
# environment variables globally without needing to reboot.
# NOTE: You will still need to restart the relevant application (including
# Terminal) to pick up the changes!
# grep -E "^setenv" /etc/launchd.conf | xargs -t -L 1 launchctl
# See http://www.digitaledgesw.com/node/31
# and http://stackoverflow.com/questions/135688/setting-environment-variables-in-os-x/
# Note that you must hardcode the paths below, don't use environment variables.
# You also need to surround multiple values in quotes, see MAVEN_OPTS example below.
setenv JAVA_VERSION 1.6
setenv JAVA_HOME /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
setenv GROOVY_HOME /Applications/Dev/groovy
setenv GRAILS_HOME /Applications/Dev/grails
setenv NEXUS_HOME /Applications/Dev/nexus/nexus-webapp
setenv JRUBY_HOME /Applications/Dev/jruby
setenv ANT_HOME /Applications/Dev/apache-ant
setenv ANT_OPTS -Xmx512M
setenv MAVEN_OPTS "-Xmx1024M -XX:MaxPermSize=512m"
setenv M2_HOME /Applications/Dev/apache-maven
setenv JMETER_HOME /Applications/Dev/jakarta-jmeter
Save your changes in vi and reboot your Mac. Or use the grep/xargs command which is shown in the code comment above.
Prove that your variables are working by opening a Terminal window and typing export and you should see your new variables. These will also be available in IntelliJ IDEA and other GUI applications you launch via Spotlight.