(Nasdaq: AMZN) won't rest until the Kindle platform is everywhere.

The e-tailer just announced a Kindle application for the Google (Nasdaq: GOOG) Android software environment, placing Amazon's Kindle store and book-reading features in reach of millions of smartphone owners. Kindle is already available as its own range of hardware gadgets, and also as software for your PC, Apple (Nasdaq: AAPL) Macintosh, anything running the iPhone operating system, and Research In Motion's (Nasdaq: RIMM) BlackBerrys.

The range of supported devices is impressive, but what's even better is the fact that your Kindle library, bookmarks, and virtual dog-eared pages transfer automatically between all of these readers. Apple's e-book software can't make that claim; neither can the Barnes & Noble (NYSE: BKS) Nook or Sony Reader, nor other competing hardware e-readers. The Nook actually runs an Android operating system, which would make Kindle available on the Nook if B&N ever makes the Android App Store available on that gadget. I'd love to see that happen, but won't hold my breath. Irony is hard to pull off sometimes.

Android support is a perfect fit for Amazon's anywhere-reader strategy. The Android platform itself is a sprawling, all-encompassing beast that currently resides mostly on cell phones but will soon expand onto tablet computers (and I guess you could call the Nook an early example of that), television sets, set-top boxes, and more. Now you'll be able to buy and read Amazon's e-books on all of those endpoints.

These are still early days in the electronic book reader market, and Amazon is wise to secure a foothold on every available platform. Whether the Kindle tablet survives an onslaught of new competition is almost irrelevant if Amazon makes its bookstore available on cell phones and tablets everywhere else anyway. As popular as the Kindle is, it's the content library that makes it a profitable project. In 2009, Amazon sold six Kindle downloads for every 10 physical books shipped, and that balance should continue to move toward digital dominance and its lucrative margins. Adding more user endpoints is just smart business.

So good job, Amazon. I do have to note that the Palm (Nasdaq: PALM) WebOS platform is not on Amazon's list of Kindle platforms. Will backing from Hewlett-Packard (NYSE: HPQ) change that oversight? Stay tuned.

Feel free to discuss e-book readers and their business impact in the comments below.

Fool contributor Anders Bylund owns shares in Google, but he holds no other position in any of the companies discussed here. Google is a Motley Fool Rule Breakers selection. Apple and are Motley Fool Stock Advisor picks. Try any of our Foolish newsletters today, free for 30 days. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.