For an informative read, the php website has announced dates for the "end of life" for PHP version 4. Among the highlights:
After December 31 this year, there will be no more releases of PHP 4.4.
Security fixes will be released on a "case by case" basis until August 8, 2008.
PHP 5 is now 3 years old, and PHP 6 is on its way.
Not sure what this means to anyone specifically, but if you are a PHP writer, it's something to think about.