That depends on how you end up hacking. Pandora Battery and MMS is the easiest and safest way (when done right). With the Pandora Battery, if a mistake IS made, then you should be able to fix it.
But yeah, read the stickies if you're going to ask such generic questions that already have answers. All the information you need is in the topic that Infinite Zero linked you. Its what I used to get it. Afterwards, if you have issues, then you can post your questions.
And I recommend you read some forum rules. It'll make everything easier. And if you have questions about a rule, PM a Moderator with your question before you make a mistake. I've done that a few times, and every time they tell me that they appreciate me messaging them before potentially breaking a rule.
So check out that topic to answer your questions, check out some forum rules for future reference, and enjoy your stay here at GBATemp.
Oh, BTW, FileTrip is a great place for downloads needed for PSP hacking and homebrew, ShopTemp is a good place to look for parts and accessories (I also like Price Angels), and AskGBATemp (a new service), is a great place to ask for help when its just a question, not a discussion topic. Learn the ropes, and this will quickly be one of your favorite places to be.