There is a lot of activity on the eBook front: Sony earlier announced that they would be moving towards supporting the open ePub eBook format on their eReaders, and they are expected to announce a new eReader that incorporates cellular data connectivity. Barnes and Noble announced this week that they are partnering with Irex Technologies and will come out with a new device later this year.

But with all the hoopla and promise, one thing missing from a lot of coverage is the software side of things. That is where the eBook eBattles will be fought and won.

eBooks are beginning to take hold for a lot of different reasons: finally there are enough titles available (although in a confusing array of formats and readers). Prices on the devices have come down and quality has gone up. Prices on the eBook titles themselves are at parity with the mass market paperbacks. The size and quality of the screens is approaching that of printed paper. Battery life is reasonable.

All of this may be well and good, but the real reason that eBooks are doing well is that the software is finally catching up with the hardware. Why so? Because you need a great combination of eReader software along with Web storefronts that offer the books for sale and allow people to shop and discover books that they want to download to their readers. Some of the people that design the Web stores that offer up the eBooks are getting some clue here. The best example is Amazon’s Kindle storefront. Why? Because first and foremost, they know how to sell books online. Inside of about 35 seconds, I can find and purchase an eBook, and in another 35 seconds, have it in my hot little hands and start reading. It is hard to beat that kind of delivery time.

Sony’s Web store, ebookstore.sony.com, comes in second, such as trying to find bargains. On both you can sort eBooks by price, but because Amazon offers so many free eBooks, it is hard to find current titles. Sony does a better job. Sadly, in order to buy an eBook from Sony, you need their desktop client software. B&N.com is just plain miserable.

My choice of eReader is to use the Kindle app that runs on the iPhone/iPod touch. I don’t have to carry another device around, and while the Kindle reader does drain my iPhone battery, I can deal with it. I also don’t read much beyond text: if I had a need for more graphics-rich documents, I would consider another reading device.

I have read about a dozen books from start to finish on my iPhone and found the experience to be more than satisfactory. Most of these are the sort of books that I would buy in airports and dispose of or donate almost immediately after reading. The iPhone Kindle app has a few things going for it: since I carry my phone everywhere, I am not without reading material to fill in those small time gaps during the day while I am waiting in an office for an appointment or so forth. At night, I can continue reading in bed without annoying my wife, since the screen is backlit. The page turning process is something you get used to, and the ease at which you can find a book and start reading within about a minute is great for those of us that require near-instant gratification. You can be well into the new best seller of your choice before anyone else had even time to get to the bookstore, let alone wait for the overnight Amazon shipment.

If you are in the market for an eReader and have an iPhone, it is a simple matter to download the free app, start browsing Amazon’s Kindle store, and stuff it full of eBooks. If you don’t have an iPhone, it almost makes economic sense to buy an iPod Touch and dedicate it to reading books: the cost is nearly the same as the Kindle hardware device. The downside is that you will need to be in WiFi range to download your books. On the iPhone, like the Kindle hardware, you can download over the cellular network.

If you have a Blackberry, Palm and some other PDA, then you have two choices: either the Barnes and Noble eReader or the Mobipocket eReader. Both are more cumbersome to use than the Kindle app, and require you to download books to your desktop first. I couldn’t really get the B&N app going, it seemed like it had too many moving parts.

Sony’s eReader currently lacks the communications but supports a lot of different book formats, including their own which they are phasing out by the end of the year in favor of ePub. And they have a growing culture of modders who have exposed the underlying Linux OS to do various things.

ePub-formatted books can be read on the iPhone with Stanza, but the process is also cumbersome and clunky, certainly nowhere near the experience of the Kindle. Google and others have digitized many public domain books in this format, but few of the current best sellers are in it. Amazon, by virtue of their market position, is in a better place here. They also understand how to develop Web software, something Sony — and B&N for that matter — still haven’t caught on to. The better the Web stores are, the more eBooks will be sold.

For eBooks to be truly eUniversal, Kindle needs to be able to read ePub formats, and be available on Blackberries and Palms and other larger-screen phones and PDAs. And all the various players – including Sony – need to eliminate the digital rights management that comes with your eBook, as has been reported with last month’s debacle over “1984.”

While nothing will ever replace the physical bookstore browsing experience, at least for me, I am glad to see this market continue to mature.