Bah, websites are way too expensive to buy crap from. Go down to Kragen, AutoZone, Pep Boys, Cheif Autoparts, or any good auto store, and you can find Neon lights. All you have to do is splice the power corts into a Molex Connector, and put a switch on the + wire. Simple, effective, and cheap, just like I like'z it.
(BTW, you can find other good computer mod stuff at auto stores. Window molding, for window mods, paints of all colors and types, high endurance primers, grills, some stores even have acrylic sheets, used for car windows, that can be trimmed to make a case window mod.)