There is a lot of good Catholic information on the internet. This page just offers a few good places to start.
What do Catholics believe?
Catholic Answers – straightforward and readable articles. They also do radio broadcasts that you can listen to on your computer or on your mp3 player.
EWTN – Eternal Word Television Network, another good, popular website. It has articles, television and radio programmes that are accessible to anyone free of charge. (You can watch EWTN in England if you have SKY – it is on channel 769.)
The Catechism of the Catholic Church is a comprehensive but readable summary of the Catholic faith, produced under Pope John Paul II.
New Advent – a website with the entire text of the Catholic Encyclopaedia. This was produced in 1917 and was put on the internet by voluntary workers who scanned or typed in the entire text. It remains an excellent work of reference.
How do I become a Catholic?
Here is the link to the page on Becoming a Catholic.