http://www.idiomconnection.com/
Wordpower A - Z Category
http://www.wordpower.ws/idioms/a.html
Learn English Today
http://www.learn-english-today.com/idioms/idioms_proverbs.html
The Free Dictionary, use the browse feature
http://idioms.thefreedictionary.com/get+tongue+around
(scroll down)
Using English
http://www.usingenglish.com/reference/idioms/
Idiomsite.com
http://www.idiomsite.com/
Idioms with pictures
http://humanities.byu.edu/elc/student/idioms/idiomsmain.html
Anna says:
Idioms and Phrasals are just a good way to learn a foreign LANGUAGE. There are certain differences between Idioms and Phrasal verbs. It´s easy to understand: Idioms are expressions which have a meaning that´s not (so) obvious from the individual words (of the "idiomatic expression" - THE "Idiom"). The single words have combined their "own" meaning. Phrasal verbs are verbs that consist of a verb and a particle (Prepositions, Adverbs), and they are partly separable and are following the tense patterns. What´s the best way to learn idioms ?. Use the given context and give the literal meaning of the single words as compound a new figurative context-related meaning, a new connotation. But take care, if you don´t know the literal (or even additional figurative) meanings of the single words which "merged to the idiom", then you´re in trouble as ESL-Student. You´d be screwed because there´s always an at least slight connection between the denotation of the single words and the connotation of the idiom. If you´re learning some new Idiom, and you see new words do some lookups and learn ALL the literal and figurative meanings of the single words too. BTW, Idioms are not that bad, they are "just Units" with own meaning and most of the idioms are fixed in their form.