In terms of specific requirements for getting certified, the best resource will always be pmi.org, with a direct link to the requirements: PMI site - Obtaining the Credential. The site lists a credential overview, and then there (currently) 5 handbooks for the 5 available certifications. There is also a page with how to prepare for the exam, from an administrative point of view.
If you are new to project management, then you will have to go with the CAPM certification. Then, the rest of certifications are for more and more experienced PMs. I only know well about the PMP certification, as it's the one I've got.
First step is to ensure that you meet the elgibility requirements. At the time of the posting, they are:
- for secondary degree:
- minimum five years / 60 months unique non-overlapping professional project management experience during which at least 7,500 hours were spent leading and directing project tasks
- 35 contact hours of formal education
- four-year degree:
- minimum three years / 36 months unique non-overlapping professional project management experience during which at least 4,500 hours were spent leading and directing project tasks
- 35 contact hours of formal education
If you know you want to go through the certification, I recommend you to apply for the certification first, and only afterwards to start studying - it takes some time and a lot of effort and determination, so if you are not sure, you'd rather not start it. But as you already paid for it, then you should go through the whole process.
For the study: start by browsing the A Guide to the Project Management Body of Knowledge: (Pmbok Guide). You will have some time later on to read it in detail, and learn some parts by heart, but for now just browse through it, and make sure you understand the introductory chapters, where some terms and concepts are defined. Also memorize already the knowledge areas, and the processes in each, as these will be key for your understanding.
I then recommend using Rita's manual, as the best resource for the exam preparation: PMP Exam Prep, Sixth Edition: Rita's Course in a Book for Passing the PMP Exam. It has an excellent summary of the theory, and a lot of preparatory exercises, with explanations why that answer, although sometimes your logic or experience would say differently. You can go even in more practice mode with her PM Fastrack Exam Simulation Software for the PMP Exam: Version 6 with about 1400 questions.
Unfortunately, this only book will not be enough: you will still need to read from Project Management: A Systems Approach to Planning, Scheduling, and Controlling by Harold Kerzner, and... yes, there was another one, which I cannot remember now. It will come...
Then, read through tips&tricks on the best site I had found at that time for the PMP certification: http://pmhub.net/ . People post there memory cards that helped them, hints about the exam, how they prepared and what worked better for them, why not to panic :)
While reading Rita's book, and browsing the site, you can also start reading the PMBOK standard. It's important to notice the structure of each chapter, the processes&tools that repeat in the various knowledge area processes.
You can find here a free online course: http://instructing.com/free-pmp-exam-prep/ - yes, I was surprised that they would make it available for no money, but well - why not advertise it, if it's free? :)
The bad news is that you will have to learn a lot by heart, and remember that during the exam. You will also have to go through exam simulations, and re-do them until you get the passing score - otherwise it's not worth going to the exam.
Once you are done with all these books, I suggest you do a full pass of PMBOK, then re-do an exam - just to be sure.
Or, I keep mentioning the exam: it's a 200-question exam, out of which only 175 questions count to the final passing score of 61% (or 106 questions that you have to get right). My advice is to read each question very carefully, and make sure you understand the question in the way it was put, and that you answer taking into account PMI's standard, not what you would do in real life (it might be different sometimes!).
During the 4-hour exam you can take your own breaks (no, the ticker does not stop), and I suggest that you reserve some time (an hour or so) to review all your answers. If uncertain, better not change the first answer ;)
Well, that's all story folks! Please come back after the exam and let me know if these tips helped, as well as what else did help you in passing the exam!
P.S.: If you want even more resources on project management and PMP certification, you can also browse this small site