Those big blue and whites are a great and also cheap way to get around Manhattan. Buses run 24/7 and like the subway system they too have been recently updated. The front of the buses have lighted signs that shows the line. Maps of the route maps and schedules are posted in the city at bus stations and stops. You can always get a current map and schedule from the mta:
Bus Schedules and maps: www.mta.info/nyct/bus/
You should use the Metro card-same as the subway for the bus. Bus drivers do not make change and they don't accept american express. So you need exact change if you want to use cash.
New York City Online Bus & Subway Directions
HopStop is a city transit guide,
providing door-to-door subway and bus
directions and maps for New York City.