You know that big battle between Apple's iPad and Amazon's Kindle for the growing electronic book market? Well, for Amazon, it's all good. The online retailer has begun selling the iPad directly through its website. So Amazon will be making some money off sales of the popular iPad, as well as hawking its own lineup of Kindle readers.

It's another sign that Amazon, despite its heavy promotion of the Kindle, isn't shy about tapping into the success of the iPad. Amazon has its own Kindle app for iPad — and for the iPhone, iPod touch and a range of other devices — allowing people to buy and read its e-books across the multiple platforms.

That's not to say that Amazon is giving up on Kindle the device. The company just introduced a pair of next-generation Kindles and has begun to sell them through brick-and-mortar retailers like Target (which is carrying the iPad as well). But Amazon is also a major seller of electronics itself — so adding the iPad to its selection makes sense.

Amazon, which has repeatedly cut the price on Kindles (the cheapest Wi-Fi-only version is $139), appears to be aiming for the mass consumer, leaving the more expensive iPad to take the higher end of the market. And now Amazon is selling both devices.

Looks like Amazon is currently selling the 32GB and 64GB Wi-Fi iPads, with third-party merchants selling other iPad models on the Amazon site.

I've reached out to Amazon and Apple for comment and will update if I hear back.

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