Google left a step out of its description of how to set up ant 1.7. If you stop at their instructions without following the following link, you'll still be using ant 1.6.5 (or whatever) rather than 1.7 if it wasn't already there by default.

Wooden Fish :: Installation of Ant on OS X:

Assuming the default shell of your Terminal is bash; make sure the following lines are in the bashrc file. You can find the file under /etc.

1. export ANT_HOME=/usr/local/ant
2. export PATH=${PATH}:${ANT_HOME}/bin