Where can i find apartment or a room to share in Brooklyn,Harlem or any part in NY not more than 250$/month?

I'll be @ New York on October 2011 and i'll stay their for 1 or 2 months ... and i'm looking for a room or an apartment to share near to a bus station or a Metro so that transportation can be easy .. and in range from 150 $ to 250 $ - 300 $ per month .. in any part in NY "Manhattan , Brooklyn are preferred " ..if not available so any part in NY but not more than 250 - 300 $ per month.