WordPress MU

My WPMU installations has Spam karma 2 installed, but it rejects a lot of valid messages as spam. In theory, when I recover these messages, the system will 'learn' that the reasons for doing that were wrong, and the next time it won't do it again (am I right?), but meanwhile, I only recover the messages for the blogs whose owners contact me about that issue.

Is there any way to see the global queue of messages that SK has marked as spam?

no, each blog has its own spam table. so you can't ahve an overview of caught spam unless you code it.