cycling has been discussed a lot on this forum, so rather then repeating everything, i think it would be easier for you to check the link at the top right of the page (next to the pic of the week

and also the faq's, and i think there's a forum section dedicated on cycling only.) i will just say that you need to go to a pet shop and get testing kits that will test ammonia, nitrite, and nitrate (thats 3 different tests) and then read about how to use them during the cycling of your tank. if something in the cycling info is not clear, feel free to ask specific questions

good luck with your fish