Online Chinese Course

http://hanyu.com.cn/en/default.asp
The largest of its kind and it is free.

Online Language Assistant

http://www.oneglobe.com/OLA

You can read, write, speak and listen to each other (or to the computer) in Chinese, Spanish, and English. They have a number of options:

-- Take a prepared lesson with a partner
-- Take a prepared lesson with the computer
-- Speak freely with a partner
-- Speak directly to the computer (experimental)
-- Join a group discussion

The interface is easy to use, and you can send email or feedback if you have any questions or suggestions.

Language Exchange

http://mylanguageexchange.com

Users can create a free profile asking members from more than 100 countries to contact them and become e-mail, VoIP or online chat buddies.

Traditional characters and simplified characters conversion

http://www.ee-studio.com/tools/sim_tra.html

Add tone marks to pinyin

http://www.all-day-breakfast.com/chinese/big5-simple.html

http://www.chinese-forums.com/viewtopic.php?p=19713>

http://www.mandarintools.com/addpyfile.html
 

Pinyin Font Converter
http://www.foolsworkshop.com/pfc.html 

In order to input romanized Chinese in Pinyin using the 4 tones of Mandarin Chinese, special fonts are used to mark vowels with tones. A variety of these fonts are available online. The Pinyin Font Converter converts texts between some of the most popular Pinyin fonts that are available for Windows and Macintosh.
 

Annotation tool

http://www-rohan.sdsu.edu/~chinese/annotate.html

Powerful tool to assist you with you reading. You can paste a reading text, press a
button and get an annotation with a glossary and pinyin marks.
 

Online dictionaries

Chinese-English dictionary
http://www.ok88.com/go/svc/ecdict.html
Type a word in English, you will get its Chinese equivalent.

Chinese-English dictionary
http://www.mandarintools.com/worddict.html
Type or paste a word in Chinese, you will get its English equivalent.

Simplified characters
http://zhongwen.com/jian.htm
Click on any character to see its simplified form (and its definition and etymology).

Chinese Character Pronunciations
http://www.ocrat.com/ocrat/reaf/

http://www.ocrat.com/ocrat/chargif/
Input (copy-and-paste) any Chinese text and obtain the transliterated pronunciation of each Chinese character. Follow links to online Chinese magazines and use this application to lookup pronunciations of unfamiliar words.

Flashcards

Character flash cards
http://www.mandarintools.com/

http://www.wfu.edu/~moran/flshcrds.html
printable flashcards for learning characters

http://www.foolsworkshop.com/fw.html
flashcard wizard

A is for Love
http://www.chinapage.com/flash/love.html
This is a set of Flash Cards for learning Chinese. The face card shows a Chinese word. Click on the word will flip the card over, where the pronunciation and meaning are given.

Chinese Character Flashcards
http://www.erols.com/eepeter/flashcard.html
a Java applet to assist in the learning of Chinese characters

Flashcards
http://www.wfu.edu/~moran/flashcards.html
with a week by week schedule

Flashcards for Chinese textbooks
http://www.yellowbridge.com/flashcards
Free flashcards for Integrated Chinese, Beginners Chinese and Intermediate Chinese.

Bell Labs Mandarin Text-to-Speech Synthesis
http://www.bell-labs.com/project/tts/mandarin.html
(traditional characters)
http://www.bell-labs.com/project/tts/mandarin-gb.html
(simplified characters)
Type Chinese characters or pinyin, sound will be generated automatically.

Translation tools

Chinese Dragon Writer
http://www.jics.com/LNGCHI.htm
provides easy English to Chinese phrase translation input

Free Chinese to English language translation services online
http://www.lingo24.com/contextrans-chinese-english-translation-service.html
ContexTrans will aid in your understanding of Chinese, in particular the context in which Chinese is used. By drawing on a comprehensive database of professional human translations we can show you real-world samples that include your word or phrase.

Parasaurus Rex Chinese – alternative phrase finder/thesaurus
http://www.lingo24.com/parasaurus-chinese.html
If you have a passion for the Chinese language and want to broaden your linguistic horizons then we palce a fascinating tool at your disposal - Parasaurus Rex Chinese. The joy of languages is in their variation. Why stick with one translation time and time again when there are often so many alternatives? We'll prompt you with alternative words and their context and you can take your pick. Go on - spice up your language!