WordPress MU

Hi,

Is there anyway i can add some code to the top of the index.php file automatically?
Every time i upgrade i have to put the code back. I use it as password protection to all the blogs within my domain.
I was thinking a mu plugin would be the answer but have no idea on how to do it!

Thanks

James

You could try putting it in wp-config.php. That's close to the first of the load process and doesn't get replaced on upgrade.