To create a haven for wildlife in your own backyard you'll need to provide food (native plants preferable), water (a dripper is a must!) and shelter (birdhouses, shrubbery, brushpiles, etc). For lots of neat ideas contact the National Wildlife Federation who has certified thousands of backyard habitats throughout the United States.
go to: www.nwf.org and click on "Certify Your Backyard"
or call 800-822-9919 for more information
Other organizations that certify backyard habitats, campuses, golf courses, or corporate properties include:
Audubon International http://acsp.auduboninternational.org/
The United State Department of Agriculture www.nrcs.usda.gov/feature/backyard/
The Humane Society of the United States www.hsus.org/wildlife/wildlife_and_habitat_protection_programs/