LED displays with Linux?

Timothy asks: "It seems that everywhere I look I see articles about Linux/chickenwire based MP3 players for cars that utilize a LED display instead of an actual computer screen for outputting track information and such. My question for you is simple: where can I find information on buying/using a LED display in Linux. Where can you buy them, what's an average cost for one (so I could gauge what's listed)? Would it hook up to a serial/com device? Do you need a special card to interface it into a computer system? How would you go about writing information to the LED and such?"