The defintion on cyberangels.org is good. The rest of the stuff about hacking is a bunch of krud, like
How can I tell if my computer has been "hacked" or broken into?
Some telltale symptoms are:
-Mysterious files suddenly appearing.
-CD drawer opening and closing by itself
-Runtime errors in MS Outlook/Outlook Express.
-Finding emails in your sent items folder that you didn't send.
-Files moved or deleted unexpectedly.
-Icons on your desktop or toolbars are blank or missing.
-Mouse feels sluggish, like someone else is trying to control it.
My favourite ignorant remark is the last one, Mouse feels sluggish, like someone else is trying to control it...That's possible in a server/trojan but highly unlikely...