It is important to cite your sources for two basic reasons:
1. You need to know how to find the source again to check your information, change your information, find more information....
2. You need to acknowledge your sources for ethical reasons, to satisfy copyright and to be honest about where you got some of your information and ideas. Remember, it is better to give too much credit, rather than not enough.
Check this out for a ways to create you own bibliography or use NoodleBib to help you.