There is a lot of information available about Dallas. For a great local overview visit Gil R. Glover's Dallas View, a personal webpage. Other websites that offer trip planners, maps, history and myriad other details include the Dallas Historical Society, Dallas City Hall (which features an interactive map section), and the Dallas Chamber of Commerce (which has a Trip Planner and interactive map).
For up-to-date entertainment, arts and dining listings and ratings the following websites will tell you what you need to know;
Dallas Observer Alternative Newspaper
If you just love books these travel guides offer information in detail: Frommer’s Texas Third Edition, 2005, Wiley Publishing Inc., Baird, Jarolim, Peterson & Schlecht
Lonely Planet: Texas, 2002, Lonely Planet Publications Pty Ltd, Fanselow, Bain, Bedford, Croom, Root; as well as amusing explanations and anecdotes: Dallas Uncovered, 1995, Republic of Texas Press, Larenda Lyles Roberts.
And, finally, The Lusty Texans of Dallas, 1951, E.P. Dutton and Company, Inc., by John William Rogers will give that true Texan inspired insight into Big D's past.