Where does PEAR install Drush? I installed Drush using the PEAR option mentioned on the Drush project page, but I can't find the location of where it was installed.

Does anybody know the default installation location?

Specifically, I can't find the location of the drush.rc.php file to edit and add multiple sites to.
On Unix or OS X, you can use which drush to learn the location. On Windows, it is where drush from the command line.