The New York Times announced today that it will start charging for online content at the beginning of 2011. The company has settled on a plan that will allow readers to read a limited number of articles each month for free, then require them to pay for more.

The announcement left a lot of questions unanswered, including the number of free articles readers will be allowed to receive, the rate they’ll have to pay for more, and how usage will be measured. They did, however, say that print subscribers will receive free access to online content.

Before we get too excited about this, it’s worth noting that we’ve been here before. The NY Times has tried to charge for content on two previous occasions, the latest being a charge for select op-ed columnists, but they gave up on that in 2007. So the new plan is 11 months off, sketchy, and may or may not work. It’s an important announcement, but not the end of life as we know it.

Keep in mind, too, that the New York Times, like dozens of other newspapers and magazines, is already charging for content, via Amazon’s Kindle e-reader. For $13.99 a month, you can get the whole newspaper on your Kindle. Sure, you can get it free online (for now), but people seem to be willing to pay for the convenience of a wireless subscription.

Which dovetails into the question of whether today’s announcement has anything to do with next week’s rollout of a rumored Apple table/reader. According to a lot of published reports (mostly based on unnamed sources), the Apple announcement will include news of subscription agreements with book, newspaper and magazine publishers.

It’s no secret that a lot of publications are unhappy with Amazon’s terms, feeling that the book giant is taking too big a slice of the pie. An arrangement that makes subscriptions more attractive via the Apple tablet could be a game changer in the same way iTunes was for music. Indeed, the battle over the tablet market may have less to do with hardware than with payment terms.