How can I get a list of plugins and which blogs are using them?

I’m about to upgrade my WordPress MU installation to wordpress 3

Before I update, I want to find out which blogs use which plugins.

I don’t see a way to do that in the UI, is there?

What about a query of the mysql database?

Thanks

take a look at Plugin Commander which is a plugin management plugin for multi-site mode, which allows further control on network-activated plugins.