Super-duper favorite sites:

Gardenweb - The forums provide very helpful advice; registration is free.

Backyard Gardener.com

Garden Decor at BlossomSwap

Garden Guides

ILovePlants.com

Molbaks - Even though this site is for a nursery in Washington state, they offer great care sheets (in .pdf format) for outdoor and indoor plants via the "horticultural information" link.

Virtual Gardener - "an online magazine with organic roots"

Houseplant Info:

PlantCare.com

The Garden Helper's House Plant Care and Cultivation Guides

Windowbox

Favorite houseplants:

heartleaf philodendron (philodendron oxycardium); also known as cordatum vine, parlor ivy, and sweetheart vine

devil's ivy (pothos)

spider plant (chlorophytuni comosum); also known as airplane plant

chinese evergreen (aglaonema)

arrowhead vine (syngonium podophyllum); also known as nepthytis, african evergreen, goosefoot plant

Wildlife:

Defenders of Wildlife

National Wildlife Federation

Opossum Society of the United States

Wildlife Conservation Society

Wildlife Forever

Birds:

National Audubon Society and the Atlanta Audubon Society

Nutty Birdwatcher - good source of info for Eastern U.S. birds

WhatBird.com

Bubba & Friends - birds of prey rescue organization in Griffin, GA