I've solved the problem.
I had this popping up semi-regularly, and I've never installed an app that deals with facebook. It appears to be inherent functionality in the droid. I'm confident it's nothing malicious, but it is annoying, and I've figured out how to get rid of it.
From your home page press menu, then choose settings. Select "Applications" then "Manage applications". If you're running droid OS 2.1 then you'll probably need to press the menu button and change the filter so that it show all or running, instead of just third party. On droid 2.2 it's a tab at the top to choose which you want to see. If you have the notice problem currently, it's obviously running, so go to the running tab, and find "SNSaccount". You can choose Force Stop and the notice will go away. It's not possible to uninstall it, so it may come back after you restart your phone. I also chose "clear data", not sure yet if that will help.
In short: find SNSaccount and force close it.