During the development of this website, we found the following sites to be very helpful toward learning Chinese.
www.pin1yin1.com You can use this site to convert any Chinese character to Pinyin. On the main page, you can also click on the Chinese characters below the conversion input box, it will show you all the phrases associated with that character. The phrase page is very comprehensive with good English translation. It is a great tool to enhance your Pinyin ability and learn new phrases.
www.mdbg.net You can use this site to translate between Chinese and English. You can enter word, phrase, or sentence, and it will give you fairly accurate translation. You can use this site to translate from Chinese to English or from English to Chinese.
translate.google.com Google also has a very good engine to translate between Chinese and English. I found this engine to be very effective in translating vocabulary and phrases, but it is not very accurate when you try to translate sentences.