Technically Exec-PHP executes code inside of <?php ?> tags by just wrapping your whole text into ?> <?php tags and hand it over to the PHP eval() function. By that no parsing of your code needs to be done by the plugin itself. Although the plugin adds some security features, it is not recommended to use the plugin in WordPress installations with untrusted users.

With Exec-PHP you can execute PHP code in the excerpt and the content portion of your posts and pages (in the following called articles) as also as in text widgets. To execute code, just type in the PHP code as you usually would.

Pricing: Free
Requirements: -
Source: http://bluesome.net/post/2005/08/18/50/