Ambika,
A good place to start is on the PMI website, login and then go to your "dashboard". There you will find a pie chart showing your PDU progress. On the PMI website you will also find lots of webinars etc.. that you can use to earn PDUs. You can also earn PDUs by attending local chapter meetings which has the added benefit of networking. You can also earn up to 8 PDUs through the project management work you may be doing in your job. There is Cornelius' PDU Podcast as well. There are many ways to earn PDUs and the PMI website will have all of the details. The key is to start soon, make a plan and be consistent. Good luck.
Cheers,
Mark