GameFAQs: Ultima IV - FAQs, walkthroughs and town script. - http://www.gamefaqs.com/computer/doswin/game/562660.html
Ultima IV: Gaining Virtue - List of actions that alter your virtue in the game. - http://martin.brenner.de/ultima/virtuechanges.html
xu4 - Ultima IV Recreated - A remake of the classic computer game Ultima IV for modern operating systems. - http://xu4.sourceforge.net/
Ultima IV: The Dawn of Virtue - A fan remake project with 3D rendered isometric graphics. - http://www.hut.fi/~jtpelto2/ultima4/
Ultima Personality Test - Virtue based class-determination questions, game crib sheet, and character files. - http://www.tk421.net/ultima/
Ultima IV: Quest of the Avatar - Origin's official site. World and dungeon maps, walkthough, documentation, and music files. - http://www.uo.com/archive/ultima4/