done this before, depends on the personality. if they're vindictive, search for an apt in secret and just leave, it's not like you need him for referrals but do give time to inform him of "i have this great opportunity I'm going to try out."
if the person is cool, you just want something more fulfilling, then yeah, what zenny said. if someone's gonna hate that you want to be self-sufficient or are looking for new experiences, then they're gunna hate. if you're helping him out tons financially, be a good human being and let them know beforehand.
that said, I'm going to bounce from the dl, no not delete the acct. but i'm not playing games right now and i need to focus on my prospectus writing, because, yeah, due september. so I'm on skype as jewjewls, but my extent here will be peepin' and creepin'. good spring/summer, and OMG ill totally creep on dlcon pics. its safe to say that if we dont talk this doesnt matter, but if we do heads up.