I installed Apache2 along with PHP5 on my laptop. Right away I ran into the problem that the "Apache2" service was not registered. Something else was using up port 80. With the help of netstat -lao and a process monitor that actually shows the process IDs I figured out that Skype was the issue. Skype hogs port 80 by default. After disabling it and running apache2.exe -k install -n Apache2 the problem was solved.
Then I tested several of our projects on it. They all seem to work fairly well. Our web framework classes all inhert from the same base class, which used __construct() and __destruct(), something that PHP5 now does natively. With only a minor change the software is now backward compatible with PHP4, yet we're able to take advantage of PHP5's new constructor format. Very nice.