In addition to using the websites already listed, if you have a smartphone, I also highly recommend downloading Pleco Chinese dictionary. It's a free app, and very comprehensive. Whenver you learn a new character, you can look it up in the dictionary and go to the "characters" tab, it will tell you what its radical components are are what they mean. It's worth noting that many radicals are more for their phonetic component than their meaning, some of these you will just learn with time.

The parts of characters are called "radicals". If you google "Chinese radicals" you'll find some good resources. Here are a few:

http://www.yellowbridge.com/chinese/radicals.php

http://www.clearchinese.com/chinese-writing/radicals1.htm

Check out www.zhongwen.com

I CAN BE YOUR LIVING DICTIONARY.