Hy!
This is my first (but not the last) officially released plugin!

* Plugin Info
- Plugin Name: Inside Posts
- Plugin Version: 0.2
- Mybb Compatibility: 1.2x
- Author: MyBB Romania
- Copyright: © 2008 MyBB Romania
- Website: http://mybbromania.com
- Description: Display custom content inside posts
- Price: Always FREE

* Install:
- Upload the inc/plugins/insideposts.php;
- Activate the plugin (Inside Posts) in the plugin manager;
- Insert your custom content and activate (in Admin CP> Board Settings > Change > Inside Posts).

The rest is self explanatory.

* Uninstall:
- Deactivate the Inside Posts plugin in plugin manager.

* Upgrade:
- Deactivate previous version of Inside Posts plugin;
- Upload insideposts.php from insidepost.zip over inc/plugins/insideposts.php file;
- Activate new version of plugin (Inside Posts) in plugin manager.

Thank you,
MyBB Romania

Quelle: http://mods.mybboard.net/archive/view/inside-posts