The main thing is getting the LCD controller: is there some chip or PCB somewhere on (or inside maybe?) the housing of LCD display? If not, you'll find the chip on the tablet's mainboard, and by searching for it's name, you might find a complete controller with VGA/S-Video/Composite/RGB input (something that's supported by controller), and you hook up the display there.
Simpler way, how I'd do it, would be to look up for the datasheet of chip on the Google, and then wire the inputs according to pinout in datasheet.
It might take time to find out how to power it up and how to feed it with image, but in the end it should work - currently I'm working on a same thing, but with LCD taken from portable DVD player with controller in the LCD housing.