English Plus+
Grammar Slammer Glossary: Prepositions
This site offers a basic definition of prepositions, along with a chart of the most common ones. Some of the prepositions listed serve as a hypertext link to more detailed information on that specific word.
Robin L. Simmons
Grammar Bytes: Prepositions
This site offers basic but very thorough information on prepositions and prepositional phrases. Uses visual images and simple explanations, including a more detailed discussion of how some prepositional phrases also serve as...
University of Ottawa (Canada)
Hyper Grammar: The Parts of Speech
This grammar tutorial site offers a thorough discussion of the various parts of speech.
University of Victoria (Canada)
Elc Study Zone: Basic Prepositions
This site explains the various uses for "in," "on," and "at" in phrases referring to transportation, time, and communications (TV, radio, etc.). Also links to a practice exercise.
Online Writing Lab at Purdue University
Purdue University Owl: Prepositions of Location: At, In, On
Maintained by the Purdue University Writing Lab, this tutorial focuses specifically on the three prepositions mentioned in the title: "at", "in", and "on". Explains spatial relationships and examines "in" and "on" more closely.
Other
Tidewater Community College: Writing Center: Prepositional Phrases
Questions to ask to help identify prepositions and their purpose within each sentence. Offers list of common prepositions and examples of usage.
University of Washington
University of Washington: Grammar: Prepositions
Mary Nell Sorensen teaches ESL at the University of Washington. Her page provides grammar tutorials for all the parts of speech. This specific pages covers prepositions