pg_dump -C -h src_server -U src_user src_db_name | psql -h dst_server -U dst_user dst_db_name

Important database copy performance boost!

When both db servers are using ssl=true in postgresql.conf the copy ran at about 5MBit/sec on a gigabit LAN
When I disabled SSL on both servers (ssl=false) and restarted postgresql, the copy ran at 50-70MBit/sec (more than 10x faster)
You might want to consider disabling ssl while you perform the copy.