Hello,
If this is your first time entering this website, good job!
It shows that you are serious about learning how to become a 
better person in life.
This website will hopefully teach you how to tolerate other people
and be less discriminating. At the top there is a navigation bar which
will guide you to various sites which do their best to promote
tolerance and fight Hate. They also have articles for you to read and
learn why it is better to love instead of hate others.
So.. What is prejudice?
Simply put, prejudice is bias. Prejudice refers to the negative opinions, judgments, beliefs, and feelings we hold about individuals because of their membership in certain groups or categories. When these negative views lead us to act in certain ways toward these individuals and groups, the result is discrimination, the action taken due to prejudice. Discrimination can be expressed direct (talking bad to/about a person, treating someone bad.. etc) or indirect (by thinking badly about someone).
To read more about Prejudice or Discrimination go to any of these links:
Prejudice (Wikipedia)
Understanding Prejudice 
Discrimination
What to tell your Child about Prejudice
You can fight Hate in many ways and how to fight Hate, Prejudice
and Discrimination is best described in these websites:
Tolerance.org
Canadian Race Relation Foundations
Youth Forums against Racism
BritKid

Or you can just refer back to the Nagivation bar at the top of the page to access these websites.