If you go to the Vegetarian Resource Group website, they have extensive information about popular chain restaurant vegan and vegetarian options (look at their restaurant chain tab).  They also have a book out called "Meatless Meals for Working People" that includes extensive detailed information about chain restaurants and which options are vegan.  

I rarely eat out so I can't help too much, but there are sites like happy cow and vegetarian dining that you can type in your area and get a list of restaurants with vegan and vegetarian options.  People write reviews all the time on those sites.  Also, you could just pick a restaurant you want to try, then call ahead and ask about their food.  Many offer online menus to look over.  I have done this before and asked ahead if certain items, such as bread or dressings, are vegan.