WordPress MU

Is there a way to have a sitewide announcement bar controllable from a single point? I don't mind adding code to all the pages, just when the message needs to be changed, it can be controlled at a single point. Also, is there a maintenance mode that closes access to all blogs and gives a message? Although preferably giving access to admins who login. Thanks for your help.

Have you considered this plugin?

No, not in the dashboard. Preferably for all users - registered or otherwise - to view.

I'm sure it could be modified to do both, actually.

How would I do that?

There's a neat little function that tosses out the message. Just place a call to that function wherever you want the message to be displayed.

Edit:

The function is: admin_message_output()

Thanks,
Andrew

If I want it to be displayed on EVERY page of the site, would I have to hardcode it onto EVERY SINGLE page?

No. That's what theme hooks are for. IE: wp_footer.

Is it possible to have a server-wide hook?

That's what theme hooks are for. IE: wp_footer.

Please see:

http://wordpress.org/search/wp_footer