Step 1: First Thing
First, go into safari and type jailbreakme.com
Second, find the thing beside "Cydia" and it should be green and have "free" on it.
Thrid, double tap the free and it should install it like an app.
It takes about 10 seconds.
NOW U HAVE CYDIA!!!!!
Step 2: I Dont..
i dont know what versions you have to have to do it, all i know is if u have 4.2.1 or lower, you're probably going to get it working. please comment and/or subscribe