Many of us have only a general knowledge of where various forms of wildlife live. It's not something that we usually need concern ourselves with in our day-to-day lives, but it's certainly relevant when thinking about the planet's biodiversity and environment. There's more to ecosystem variation than "jungle," "forest," "desert," and "plains;" each of the over 800 "ecoregions" recognized by biologists has its own set of niches for wildlife. Unless you're a specialist in conservation biology, you're unlikely to be in a position to learn them all.
Fortunately, the World Wildlife Fund has opened up an online database of wildlife locations called the WildFinder, covering over 30,000 species across four major groups (amphibians, reptiles, birds and mammals). Enter an animal name -- common or scientific, whole or fragment -- and the WildFinder will come up with a list of locations in which it can be found, along with data about the specific characteristics of each spot. Or you can pick a spot on the map and find out what lives there. Be careful with that one, though -- some regions have an incredible variety of organisms, and pages with 1000+ entries can take awhile to load.
Each animal listing includes links to "general" and "detailed" information on the home ecoregions. The "general" set is well-presented, but the "detailed" pages are quite impressive. The ecoregion information pages go into more detail than the information about the animals themselves (in fact, when you click on the link for images of the requested animal, it takes you to a google image page searching on its scientific name). To me, this is actually very useful -- rich discussions of animal behavior and the like are easier to come by than good material on regional ecosystems. The detailed ecoregion pages list characteristics such as biodiversity status, current conditions, threats and a justification for distinguishing the location as a separate ecoregion.
Knowing where different animals live is an important part of understanding the threats they face from climate change and other human causes. Wildlife is often the silent victim of human conflicts, for example, either caught in the crossfire or hunted down by hungry soldiers or starving refugees. This, in turn, can have important implications: simian immunodeficiency virus (SIV) is older than the human form (HIV), and was possibly initially caught by a human through the consumption of chimpanzee "bushmeat."
From a biodiversity perspective, the main drawback to the WildFinder is the limit to the more "charismatic" taxa. Fish, cephalopods, arachnids, insects, etc. etc. are nowhere to be found. Perhaps they'll be there for version 2.0.