if your host supports php scripting
type
Code:
<? include 'footer.php' ?>
at the bottom of everypage where you want the copyright notice to appear
and then make a new file called footer.php and type the copyright notice into it, upload the file to your server and now wherever the include footer code appears it will grab footer.php and include it
edit: was beaten to the solution, both ways will work this one and the one mentioned above.
also, if you use the php method make sure ur html files are saved with the .php extension