It looks from your post that you are not deluded about the nature of the org. It is likely that you don't now fully appreciate the extent to which this can disrupt your life and all you have worked for.
First off, don't worry about presenting info yet. You don't know how to do it, and you will likely do more damage than good. Your first step is prevention and diagnosis of the seriousness of her case of jw-itis (the beleif that the jw are God's religion)
People (women in particular) show interest in groups like the jw because of security issues. You need to figure out why she wants to be a jw, or is showing interest. If you can fulfill that need outside of the jw, you will cause her interest in the jw to go away. Her problem isn't that she is interested in the jw, it is NEEDS to be interested in the jw.
Don't be hostile to her search for faith. Be her partner in it. You will do several things here. You will build trust and rapport with your wife's cult personality (more on that later). It will also give her a tether to reality to have you present and involved in her studies. Finally, it will give you the chance to ask important questions during her study. Don't worry about those so much. You will get plenty of help here from the boards.
I would really stress to your wife the importance of doing this together. Promise her that you are willing to acknowledge truth wherever you find it, and if this is important to her then it must be important to you. Try to get her to agree to only go to meetings together. Once she agrees to that, find all sorts of reasons to avoid meetings.
Work REALLY hard to strengthen your relationship with her. Spend as much time together as possible. When a person joins the jw, the enter into a binding agreement (you can't leave without pain). Your wife is toying with entering into a binding agreement in the midst of her agreement with you. That agreement will ALWAYS take priority of your agreement. This will serve to provide a wedge between you and your wife. Get as close to her as possible.
My to do list for you.
1. Right after you read this, order the following books: Combatting Cult Mind Control by Steven Hassan, and Releasing the Bonds by the same author as a follow up. Before you can tell your wife about the lack of truth in the jw, you have to learn how. This is a very difficult thing to do well. Read this book and you will get some insight into your wife's cult mindset. Another good book is Finding Faith by Brian McLaren. This is a good source of questions and understanding regarding the issues and pitfalls fo faith.
2. Build up trust. Take interest in her study. Take interest in the other jws. Ask questions. Be genuinely curious. Never attack the org. If you must (only if you must) talk about the org you can offer perceptions, "it seems like the jws all think the same way" rather than judgements, "jws are all brainwashed."
3. Don't freak out, but be honest about your feelings. Otherwise you will get pissed and start calling the jw a cult. If she or any jw does something creepy, acknowledge it. You need to think about and establish clear boundaries. Jw's have no respect for boundaries. When you do point out a problem with a jw, ONLY TALK ABOUT THEIR BEHAVIOR. This will be extremely difficult because jws will always hide behind their religion to justify their bad behavior.
4. A short term project is to diagnose her dubness. Based on her answers, we will have more advice for your short term strategies. Ask her the following:
"On a scale from 1 to 10 how sure she is that the jw are the right religion?"
"Ask her if the jw were wrong would she want to know?"
"Is there anything the organization could do that would convince you they couldn't be the right religion?"
"Why are you interested in the jw now?"
"Why didn't you come to me about your interest and try to include me in it as well?"
"Were there any things about the jw that bothered you?"
"Why did you never become a jw before?"
5. Hang out here and ask ALOT of questions. Ex-jw's are some of the nicest people you will ever meet. Remember, the jws have been at this for over a century. They have seen thousands of guys like you. They know every move you will make and how to head it off. Fortunately, you know their every move. Cults are painfully predictable. The folks here will let you know what to expect at every step.