Check with the hostel and let them know of your estimated check-in time. Most hostels won't have a problem as long as they know that you'll be late. If you just have a reservation and you havn't actually paid for the bed yet, many hostels will give your bed away after a certain hour unless you've made prior arangements with them.
"There is nothing in the world more helpless and
irresponsible and depraved than a man in the depths of an
ether binge, and I knew we'd get into that rotten stuff
pretty soon." - Raoul Duke