Magento and PHP5 Install Memory Error

If, when installing Magento Ecommerce, you experience some variant of this message:

Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 24 bytes) in /home/userdir/sites/mywebsite.com/public_html/magento/lib/Zend/Db/Statement/Pdo.php on line 232

The solution is simple. Just go to your

/etc/php5/apache2/php.ini*

and set memory higher than the default of 16M. The error trace indicates a minimum requirement of 24M for successful installation.‡

But you knew that already, right?

^{* php.ini may be in a different directory
‡ full disclosure: I allotted 64MB since the slice I'm using has 512MB available.}