A Three Sisters Garden consists of corn, beans and some type of gourd ( squash, pumpkin, melon) that are interplanted. This garden is the most popular example of companion planting, and has been employed by Native Americans since before Europeans arrived on this continent.
The Master Gardeners have planted and maintained such a garden at the Angel Mounds State Historic Site.
The plants consist of corn, climbing beans, and either a squash, pumpkin or melon. In keeping with tradition, choose seeds that are heirloom and open pollinated for your Three Sisters Garden.
Here is a link an article on growing a three sisters garden.