i'm testing your (great) plugin under WP3 with multisite enabled.

Many things work fine but :

I found Role groups, Role options and Role defaults under the SuperAdmin menu, but the link is déclared broken.

The link "define user options" on page "general" doesn't work.

It returns the following indications when debugging :

Notice: register_sidebar_widget is deprecated since version 2.8! Use wp_register_sidebar_widget() instead. in (…)wp-includes/functions.php on line 3234

…[truncated by admin]

Notice: is_site_admin est déprécié depuis la version 3.0! Utilisez is_super_admin() à  la place. in (…)wp-includes/functions.php on line 3234

Notice: get_current_user_id est déprécié depuis la version 3.0! Utilisez $GLOBALS['current_user']->ID à  la place. in (…)wp-includes/functions.php on 

Hoping it can help