A free online Talking English Pronunciation Dictionary - simply mouseover/tap your entry to hear it pronounced. American and British spellings, with alternative Pronunciations. Sounds are fast, clear and completely natural, pre-recorded by native speakers. Answers the question "How do you say...?".
Sounds of Speech (English) mobile application. This site contains animations of the phonetic sounds of Spanish and English. Available for each consonant and vowel is an animated articulatory diagram, a step-by-step description, and video-audio of the sound spoken in context. It is intended for students of phonetics, linguistics, and foreign language.
This site provides not only definitions, pronunciations, synonyms/antonyms, and etymologies, but also, to name a few features, real-time example sentences from Twitter, words that are used in the same context (e.g., searching for "corny" will retrieve "overblown" and "country-western" (!), and Flikr photos tagged with the word-so you can actually see what people find corny.