how is it busted? if it is always pegged hot, then the sender wire could have shorted out. just run a new wire or trace the old one.
the sender is right where Jrichker said, and it is like 4 bucks at the parts store. get a new one if you want. i highly recommend an aftermarket gauge. the stocker sucks, IMHO. you can keep the original gauge (if you get it to work) with the new gauge. just mount the stock sender somewhere else.
good luck.
depends what you want to spend. some are 10 bucks at the parts store, some are upwards of 100 bucks. anything is really better than the stocker.
install is easy if you are a little familiar with cars. run the sender, relocate the stock gauge's sender if you want, and mount your new gauge.
if you are not sure, you might want to grab a buddy and ask him if he knows to how to it; gives you a safety net.
good luck.