We propose Push-to-Peer, a peer-to-peer system to cooperatively stream video. The main departure from previous work is that content is proactively pushed to peers, and persistently stored before the actual peer-to-peer transfers. The initial content placement increases content availability and improves the use of peer uplink bandwidth. Our specific contributions are: (i) content placement and associated pull policies that allow the optimal use of uplink bandwidth; (ii) performance analysis of such policies in controlled environments such as DSL networks under ISP control; (iii) a distributed load balancing strategy for selection of serving peers.