If you're looking for an off-the-shelf solution, your best bet is probably a USB to parallel converter module and just run the standard parallel port LCD control software. Companies like Digi ( www.digi.com ) and others sells these. I'm not sure if the parallel port adaptors work well under Linux, as I haven't tested them myself yet. Has anyone done this and had success?
If you want to built a circuit, I believe Microchip ( www.microchip.com ) has a new PIC chip with USB capabilities built-into it. You could also try searching the web for a USB microcontroller or USB prototype board. I've seen small boards with a USB type B connector on them and the necessary IC's to convert the data to parallel format suitable for interfacing with a microcontroller.
That's all I can think of right now. Let us know what you find out.