Thought about this seeing another question pop up about a user agent string showing up in the poster's logs; is there a site for sysadmins to go to for finding the latest information about signatures/tell tale signs of attacks currently running wild on the network? I know google-fu can help with stringing together evidence until I find things like "I'm seeing this on my network" or "this is in my log files..." but if a worm or malware attack is fairly new, searching typical virus databases from vendors may not be up to date (plus they can put a proprietary spin on things).
Is there a good central site for sysadmins to refer to when they see a sudden uptick in particular ports being probed or a particular string showing up in a scan or unusual activity in their internal network?