How to cite my sources?

When I find a thing or a word I always go to the website to the searching page to search the words or I will go to the dictionary and find the thing or a word and also I can find the answer in the book and I will take note some importent notes and I will remember it and write down about it.
These is some website when i don't know something an i search:
www.igoogle.com
http://www.wikipedia.org/
I always find things in these website