First you Iphone has to be jailbroken. I will post a tutorial on how to jailbreak your Iphone soon. If your phone is jailbroken you need to
Go to Cydia/Sources/Manage/Edit/Add, then type ihacksrepo.com.
Go to Cydia/Sources/Manage/Edit/Add, then type sinfuliphonerepo.com
After installing these two sources on your jailbroken Iphone, you will now be able to get cracked versions of paid Cydia apps such as MyWi 4.0, adblocker, snapture, 3Gunrestrictor, screendimmer and many more.