I want to become a doctor that travels to Africa. What do you think and how do I do this?

I'll be in a four year university next year. I want to become a doctor, but not one that only works in a hospital. I want to go to 3rd world countries, particularly Africa, and help. I've seen what it's like there first hand and I'm determined to doing something.
Maybe for a few years, or a few months each year, etc.
Do I just take the same steps as any doctor?
I'll admit though, I'd still like to make money... I want to be able to support a family so I'll need it.

How do I go about doing this?

There are the obvious steps, like completing your BS and going to med school. After you complete your internships you can look into groups like Doctors Without Borders or the Red Cross. There are several international aid groups and groups state side that are in need a doctors.
Even if you decide not become a doctor, programs like the Peace Corps can give you the opportunity to help underdeveloped countries.

It will be a long road, but I applaud your desire to help those in need.

Whatever the route is to end up working in Africa, your first steps are going to be getting through your undergraduate work, then the long trek through Medical School and your Residency. I'm sure you're aware of this.

I did a simple Google search for 'Doctors who work in Africa', and the first 5 links look very informative. One was for Doctors Without Borders, an organization I've heard of and I know does good work. The link below will tell you what their specific requirements are for working with them.

Reading the websites of different organizations that work to place health professionals in poorer countries, you should be able to find an e-mail address of someone you can openly communicate with, and get their story of how they ended up working where they have.

Good luck! It sounds like it will be a very trying, yet rewarding career path.

*Edit*
In light of what Amy has said above, aiming to volunteer with one of these organizations in the between time would be a really good intermediate step to take. They'll be able to answer a lot of your questions, and it'll really help to clarify and motivate you toward your goal.