(Photo credit here.)
This can be a confusing distinction.
When it comes to taxonomy, frogs and toads are of the same order (Anura) but different families. True toads are of the family Bufonidae, while frogs belong to the family Ranidae. Some frogs have "toad" in their common name because they may bear some resemblance to a toad, but there are some distinct physical differences between the two.
Frogs live in wet environments, around water. Because of this, they have smooth, wet (or slimy) skin, and large web-footed back legs for jumping and swimming.
(Pictured: Relict Leopard Frog, via CNAH.)
Toads, on the other hand, live on dry land, so they have dry skin that is rough and "warty." Toads also have stubby back legs more suited for walking.
(Pictured: Great Plains Toad, via CNAH.)
Frogs have teeth, and toads do not. Frogs lay their eggs in clusters in the water, while toads lay eggs in long chains on plants that grow in the water. Some frogs have poison glands, but all toads have poison glands.
The Center for North American Herpitology has recently made available a checklist of all amphibians, reptiles, and turtles in Utah, found here. This checklist contains taxonomic information, photographs, and common names for all of these animals. The checklist will also help to standardize the common names of these animals, to avoid confusion and maintain consistency as taxonomic information changes.