TIgor4eg

Easy way to add php code. No need to edit functions.php in your theme directory. 
Just paste code in Admin menu and save. 
Code is highlighted with <a href="http://codepress.sourceforge.net/index.php" rel="nofollow ugc">codepress</a>.

Add Functions

With this plugin you can add new functions through admin menu, without editing your themes functions.php

Hiranthi

This plugin will help you to easily link to WordPress functions in the codex. Just put the function name between the [wp]function[/wp] shorttags and it’s linked to the page in the codex automatically.

Link to WordPress functions

Easily link to WordPress functions in the codex.

Add Functions vs Link to WordPress functions