Where can I find colored indicators for use in Cocoa?

Answer 1

You can find the images used in iChat/Mail/etc inside the InstantMessage.framework. The directory is /System/Library/Frameworks/InstantMessage.framework/Resources

You can get status-available.png, status-away.png, and status-idle.png

Of course, rather than needlessly including extra image files in your app, you could also include the InstantMessage.framework in your app and use [IMService imageNameForStatus:] to get the names of the system images for each status. See the IMService Class Reference