It's highly recommendable you don't install a leaked OS as it could void your warranty if you don't do it right. If you are not comfortable with computers, zip files, and such, you are probably better off calling your wireless carrier as they can guide you step by step on how to update via your home phone or another phone.
By the way this thread is Theme related, in the future if you have an OS question, you need to go here BlackBerry OS Discussion or here OS Beta/Hybrid Discussion! Also, as a rule of thumb, it's better if you state the model of the phone and actual OS you are on; so that people can guide you better.
