A phrase usually used in an Instant Messanger to let people know that you're going to get a bit to eat. It translates from 1337 speak to "food dude", the 0's being added for leetness.
An extra 1337 way of saying "food".
As with the simpler term "f00d", it is either used to describe an edible thing or more often as an exclamationmeaning one is going to get something to eat.