I've had a number of requests for this feature, so I've modified the unique code script so you can use it in your Wordpress posts and pages. This can be achieved by following the instructions below:

1. Download the fantastic Exec-PHP Wordpress Plugin by clicking here.

2. Install the plugin. This will allow you to execute PHP code in your Wordpress posts and pages.

3. Create a new post/page as normal, and enter the code below into the post or page, in "HTML" view.

<?php 
$p_reg_code_length = 10;    // Registration code length, characters

//-------------------------------------------
//                Functions
//-------------------------------------------

function get_code( $code_len )
{
    $code = " ";

    for ( $i = 0; $i < $code_len; $i++ )
    {
        $code[$i] = (string)rand(0, 9);
    }

    return $code;
}
$code = get_code( $p_reg_code_length ); ?> 

4. You can then write the post or page as normal, and then when you want to display the unique code on the page, simply go into HTML view and enter the following code:

<?php echo "$code"; ?> 

5. When you then publish the post or page, the above code will display the unique registration code.