You can get a free NYC bike map from any bike shop in the city. Check nyc.gov to get one by mail or download one. The map shows bike shops around the city and gives contact info for them. Many shops will rent a bike so give them a call to check their rates and get more info. Transportation Alternatives also lists bike shops, many that rent bikes if you can't wait to get the map. Their list isn't all inclusive since it just lists shops that give TA members a discount.