Go to the mall before it opens. Wear walking shoes and try to coax your little one to stay in his stroller while you get some exercise. Bring pennies to throw in the fountain, and breakfast to eat in the eatery. Search out all the McDonald's playplaces. Bring friends along.
Libraries are great resources.
Not to mention the books, of course. Churches often offer special programs for moms. Your child is in his or her own program, while you make friends with other women. Even if you are not a member of their church, most programs welcome community women with open arms. Exercise options for moms at home require a little creativity.