In delay tolerant networks (DTNs), power management will likely play a critical role in the system design. Because these networks are partitioned in nature, mobility is typically required for data routing. Since nodes must physically move to create links, there can be significant routing delays, and the network must be alive for a long enough time to be of any practical use. Therefore, a power management mechanism is an attractive approach to extending the network lifetime. We propose a power management scheme that utilizes local state information at each node to decide when to put nodes in a low-powered sleep state. A data-carrying node uses this local information to determine if it is likely to deliver its data, and thus sleep more frequently. A relay node determines if it is unlikely to be helpful in data delivery, and thus sleep more. We show that for an application rich in local information, our proposed power management scheme saves significant amounts of energy versus the AEB beaconing scheme for a desired delivery ratio.