Don't ignore it. Be informed. It exists. Here's a look at some.
BTW, just in case you are confused, go to the Catholic Answers site for the answers to the questions that are raised from these sites. I hope this exercise will prove educational.
The Catechism of the Catholic Church (CCC) provides the true teachings of the Catholic Church. Verify all Catholic doctrine there please.
The Pillar of Fire, Pillar of Truth article is a good summary of what the Catholic Church is.
As any other anti-Catholic site, this site is full of exaggerations and half-truths. Remember to verify all quotes and history yourself from valid sources.
A Singapore site. Run by a guy called Lawrence Yue. An ex-Catholic. He quotes from Catholic doctrine and dogma out of context and wrongly. An excellent example of a person who hates not the true Catholic Church, but his false and distorted perspective of it.
Jack Chick is one of the most aggressive and vehement anti-Catholic in the US.
This site is dedicated to responding to Jack Chick tracts.
An anti-Catholic site notwithstanding its title.