Blizzard Entertainment: Official site by Blizzard Entertainment. Provides patches, updates, forums and technical support

Diablo 2 Technical Support: Official Blizzard technical support information containing FAQs and search facility

DiabloII.net: Includes news, files, character profiles, monsters, spells, skills, quests, strategies, active forums, and interviews

Jarulfs Guide to Diablo and Hellfire: Official download site for the most comprehensive guide to Diablo and Hellfire