Install Blue Network Plugins to Separate Sitewide Plugins in WordPress 3.0
Do you miss the way WPMU would separate your network plugins from the others? You can add this back into WordPress Multisite with Blue Network Plugins. Simply install and activate and you’ll see your network plugins separated from the rest. This kind of set up can be helpful when you’re trying to troubleshoot Multisite issues, because you can see at a glance which plugins are operating sitewide.