The easiest way to include "fixed" information in columns to the right and left of your forum would be to add an opening table statement to "includes/header.php" and the end of the table statement in "includes/footer.php".
While we don't have information in our left and right columns, we do enclose
our forums in a table to control the look.
You can can get really wild by editing send_header and send_footer in main.inc.php.
If you want to customize the email that is sent to the originator of the post, you can change that at line 964 (vers. 5.4.3) of addpost.php. We have changed ours to read:
[:blue]$msg = "DO NOT REPLY TO THIS EMAIL.\n\n$Username $lang[REPLY_BOD] $config[title]\n\n$config[phpurl]/showthreaded.php?Cat=$Cat&Board=$Board&Number=$Mnumber\n\n$EmailBody";