Each Chinese character is associated with a radical, or is itself a radical. The radical provides a “semantic root?for the Chinese character, and helps give meaning to the Character. An analogy would be Latin roots supplying meaning and form to English words. The websites below provide a good introduction to Chinese radicals.

http://www.yellowbridge.com/language/radicals.html
This website contains a list of the 214 Chinese radicals.

http://douweosinga.com/projects/chineseradicals
This website provides a neat flashcard tools to help you learn Chinese radicals.