NOTE: These websites are mostly geared toward American English.


Oral:
For pronunciation, you can't beat the University of Iowa's Phonetics: The Sound of Spoken Language. You can see and hear American English as it is spoken, as well as German or Spanish, if you are really ambitious! The link is:
http://www.uiowa.edu/~acadtech/phonetics/#You can both listen and read the words at the same time.

Listening:
For beginning listening, it's Voice of America Special English: http://www.voanews.com/learningenglish/hom

If VOA Special English is too slow for you and you would like to hear the best American English at normal speed, try National Public Radio, http://www.npr.org.and select "Listen"

The TED Talks http://www.ted.com/, are a series of interesting lectures on various subjects. Many of them are subtitled in multiple languages. You will get the most benefit out of them by playing them with English subtitles.

Dictionary
The Longman's Dictionary of Contemporary English (LDOCE) http://www.ldoceonline.com/ is the best online dictionary for English learners. It gives definitions in clear, readable language, examples of how the words are actually used in sentences and indicates how often they are actually used in spoken an written English. If you find an English word that is not in this dictionary, don't use it! It means that the word is too old, very uncommon, or just plain misspelled.

Also, if the word you are looking up begins with a "D" or an "S" the online version even pronounces it for you in both American and British English and lets you listen to examples of how they are used in sentences. (If you want this feature with the other letters, you have to buy the paper version with the CD ROM.)