Most places with limestone bedrock have chert/flint outcrops. There is good Fort Payne chert in northern Alabama, and probably other kinds of chert scattered anywhere in the state that has limestone. . You can get a geologcal survey map and look in places where the Fort Payne formation outcrops. I think southern Al has Tallahatta quartzite (silicified sandstone) somewhere, too-it's pretty good knapping rock. There are also a bunch of sites on the web that sell flint, do a google search for flint/chert for sale. If you can make it to a knap-in, there are always a bunch of people there selling rock.
