Check out these links for specific information

The Chihuahuan Desert (general):

Chihuahuan Desert Natural History – UTEP Centennial Museum website
Chihuahuan Desert Research Center (CDRI) – Chihuahuan Desert Nature Center, Fort Davis, Texas
Film: The Chihuahuan Desert: Our North American Outback
Digital Desert Library – NMSU Desert Library

Geology and Palaeontology:

Geological History of the El Paso / Juarez Region
Permian Back-Lagoon Island and Reef Exposed in Highway Outcrop East of El Paso, Texas
Red Bluff Granite Complex
Plio-Pleistocene Vertebrate Fossils of El Paso Area
Fossils of El Paso, TX
Finding dinosaur tracks
A New Creatceous Dinosaur Tracksite in Southern New Mexico
Paleontology in New Mexico
Paleontology in Texas
Dinosaur Teeth, Eating Habits and Lifestyles

Animals:

The Mammals of Texas Online Edition
Checklist to Mammals of Carlsbad Caverns National Park
Trans Pecos Audubon Bird Checklists. Discover our Chihuahuan Desert Birds
All about Birds
Fishes of the Middle Rio Grande irrigation system
Fauna of the Chihuahuan Desert
New Mexico Mammals Field Guide
Insect identification
Butterflies of Texas
Butterflies and Moths of North America
Bug Guide
Texas Entomology
Rio Bosque Flora & Fauna
Lizards of New Mexico
New Mexico Reptile and Amphibian Species List
Torpid Turtles, Tortoises, and Terrapins – Cool Green Science
Basic Facts About Prairie Dogs
Wildlife Sightings Records – Big Bend National Park
Each and every amphibian
Any type of animal tracks
El Paso Desert

Plants:

Chihuahuan Desert Plant Database
Lady Bird Johnson Wildflower Center
Ornamental Plants for Far West Texas
Low Water-Use Landscape Plants for the Southwest
Flora of the Chihuahuan Desert 
Plants of the Gila Wilderness
Mosses of the Gila
New Mexico Flora
New Mexico Rare Plant Website
El Paso Desert
Wildflowers of the United States – List for New Mexico

Research and Conservation:

Ecobased Conservation in the Chihuahuan Desert
Eco-based Conservation in the Chihuahuan Desert – WWF
El Paso Naturally Blog
Monarch Conservation in America’s Cities Guide
Checklist of CITES species
CITES resources
CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora)  continue reading