I think people should limit the number of children they have to two or three, most definitely. As soon as you say that however, you're labelled either a communist or a fascist...or both (even though the terms are mutually exclusive).
Part of the problem is human rights (indirectly part of the problem). However, done tactfully, population can be humanely reduced. In Singapore, there are incentives for women to go through college before having children. Norway's population is very small (only 5 million - 3 million people less than in NYC alone), and in spite of immigration, and one year paid maternity leave (mandated for women by the government), Norway still retains a small population. There is an emphasis on career and on independence in Europe, and even to some extent in the USA. Furthermore, sex is recreational activity that doesn't lead to pregnancy for those humans who actually use condoms.
Another part of the problem of overpopulation is religion (directly part of the problem). The spread of AIDS in Africa among Catholics in Africa is limited only by the pope allowing married couples who may have AIDS to use condoms during sex, no one else is allowed to use condoms. The influx of Christian influence and religion in general's promotion of women as baby makers, and nothing else, the right's hatred of real sex education, and insistence on abstinence only education, and the inaccessibility and stigmas against birth control, abortion and planned parenthood providers all promote at best neglected children, and at worst, resource draining overpopulation. People need to learn that AIDS is preventable through use of condoms, that getting pregnant isn't the point of every sex session, and that homosexuality is a natural phenomenon (gay people don't often make new babies but usually adopt children - and there are many neglected children that need adopting).
In the meantime, people just need to be less keen on consumption. As hard as it is for the average joe to get through his thick skull, sometimes less is more.

I posted this on another forum. And you should have seen people whine and moan about "freedom," and "rights," and how they'd "leave the country" if there were laws on how many children they can have.

I realize it might not be entirely feasible (the manpower, and money, and management would all be astronomical), but I really would like the government to step in and say "two or fewer."

Our government says you lose your rights when you take someone else's away. Well, when people have three or more children, they are taking my rights away. They're contributing to overpopulation, taking up more than their fair share of resources, and contributing to pollution. That means the world is dirtier for me, and I die sooner. How is that fair?

But then again, it doesn't even necessarily need to go that far. Like you mentioned, if we would just educate everyone on things like overpopulation, pollution, birth control, the fact that babies born to teens have more health problems, etc. then people would be more motivated to keep their reproduction in check on their own, without us even needing to implement a "two or fewer" law.