Lonely Planet's Sumatra page - Basic travel information for Sumatra, link to a map, and some traveller comments. - http://www.lonelyplanet.com/worldguide/destinations/asia/indonesia/sumatra/
Jambie Explorer - Offers blackwater canoe adventure from berbak National Park, Sumatra Island Indonesia. With saltwater and freshwater crocodiles, migrant birds, sumatran tiger and bears. - http://www.jambiexplorer.com
Travelershub - Sumatra - Lists local demographics, history, weather and attractions. - http://www.travelershub.com/destination_guide/south_east_asia/sumatra.html