Sounds indeed like the backlight may have died. Backlighing is usually just a flourescent tube, just like you use at home but much smaller. They don't have an endless lifespan...

They CAN be replaced, but you really need to know what you are doing:

http://search.ebay.com/search/search...rclo=&saprchi=

The tube is very very fragile, andrequires you removing the screen cover, usually removing the entire panel, and disassembling the panel back. I've done this repair before, and it is usually a 30 minute job. One word of warning though; always always remove the battery and AC before doing this, and discharge the backlight power supply as they produce 1000's of volts to power the tube.