In the first episode of List-en up!, the Angie's List podcast, Marion County, Indiana lead inspector Buddy Compton mentioned that store-bought lead-testing kits can be effective for testing surface paint, but they might not detect dangerous lead in deeper layers. The Consumer Reports on Safety blog tested several of these kits and posted their results here. You might find these results helpful before purchasing a kit yourself or deciding to have potentially poisonous paint professionally tested (hurray for alliteration!)