After upgrading to OSX Lion, I discovered that both PEAR and PECL had gone missing. It turns out that you have to re-install them, but luckily it's quite simple. I found this quick guide from Ruggero De Pellegrini on Google+, and thought I would share the info to save you the confusion:
- Download the installer curl http://pear.php.net/go-pear.phar > go-pear.php
 - Start the installation procedure with sudo sudo php -q go-pear.php
 - Select a new installation base ($prefix) e.g. /usr/local
 - Proceed with the install.
 - If there is no /etc/php.ini file yet, copy the default sudo cp /etc/php.ini.default /etc/php.ini
 - Edit /etc/php.ini and change the line ;include_path = ".:/php/includes" to include_path = ".:/usr/local/share/pear"
 - Add /usr/local/bin/ to your path if you haven't already, e.g. in .profile
 
To test it, run either pecl or pear in Terminal.app and see if it works.
Thanks for posting - I found a few of these "pear on lion" walkthroughs, yours was the first one to work!