WordPress MU

General question : is there some page/website about developping plugin specificly for wpMu ?

I'm use to develop them for standalone wp, but I need help about "is there a simple mean to have an 'sitewide option' ?".
More precisely, I need that all blogs have access to the same option whose value is defined by the sitewide-administrator.

Someone did that ?

get_site_option, vice get_option.

Same with update_option, etc.

Check wp-includes/wpmu-functions.php

Surely I am not the first to write this up, but I just posted about how to write a WPMU plugin.