The interview process is, like most things at P&G, a well-defined process. First, you must apply online at pg.com. Secondly, you will receive a link to an online assessment which you MUST pass in order to proceed in the interview process. The questions are behavioral-based, and there's really no way to cheat it or beat it, so just be honest.
After the online assessment, you sort of enter the black hole. If you know someone at P&G, it's really good to make that contact so your file can get to the attention of an HR recruiter. Pending your score on the online assessment, you will have a telephone interview with HR, which will be all behavior-based (tell me about a time you led a team, etc.). Answering in the Context-Action-Result format is imperative - you won't move forward if you don't respond in this fashion. It's perfectly acceptable (and encouraged) to use examples from work, school, and community functions.
Pending that interview, you will then be invited to an onsite interview where you will typically meet with three or four marketers from various levels. Interviews are typically two on one and, like the HR interview, will be behavioral. Additionally, you MUST use the Context-Action-Result format. Have quantifiable results, and display a passion for winning.
You should receive feedback within a few days - if you make it to the final rounds, you're almost there!