4 links
Brooklyn Botanic Garden: Rain Gardens
bbg.org
Guide to creating a garden with US region-specific plant lists.
Clean Water Atlanta: Rain Gardens for Home Landscapes
cleanwateratlanta.org
Instructions on creating a garden and a native plant list for Georgia gardeners.
Rain Gardens of West Michigan
raingardens.org
Citizen-based environmental advocacy and education organization. Includes news, guides, garden plans, demonstration gardens, and rain barrel information.
State of Illinois: Rain Garden Initiative
standingupforillinois.org
Includes introduction, videos, native plant lists, and links.