It has a catchy name, a nice design, and the right price tag—free. But is Kensington’s new Rise & Shine Clock & Weather app going to succeed at its apparent task: helping the company to sell its new $40 Nightstand Charging Dock for iPhone? Or is it the other way around: are users supposed to learn about and purchase the Dock first, then show up to the App Store to collect their free clock app?

We learned about the Nightstand Charging Dock and this software prior to its official announcement today, and weren’t exactly sure what to make of this particular bundling idea. iPhone and iPod charging cables are free with their devices, of course, and most combination wall chargers and cables retail for $30 or less. Kensington’s twist adds a big plastic block to the end of the Dock Connector, enabling a connected iPod touch or iPhone to stand up on either its side or its bottom. This dock design displays the app for the user to see rather than laying the device flat on its back, and keeps the unit charged while the app runs, but apparently doesn’t do anything else.

So between the app and that plastic block addition, there’s supposed to be $10 of value that justifies the higher than typical purchase price of the charger. For sure, the app is nicely designed—much like most of the iPod and iPhone accessories Kensington has released over the past five or so years. It flips between three types of clock displays, one mimicking an old-fashioned digital clock, another replicating a flip-based analog clock, and the third using a futuristic font and reflective design that’s similar to the company’s logo and packaging. Portrait and landscape modes are supported for each clock, and they all look nice.

At the bottom of each screen is simplified weather and date information, which can be clicked on to open a five-day forecast complete with iconography; a separate settings screen lets the user pick colors and make other adjustments that are in some cases clock-dependent. You can dim the screen by merely running your finger over the display, a cute trick that none of the hardware-based iPod or iPhone alarm clocks released to date makes so simple. It’s suddenly becoming easier to picture the iPod touch and iPhone as replacements for the clocks in speaker systems, though the question of whether users want to keep their devices’ screens on full-time or depend upon having their devices handy at all times for clock purposes is open for some debate. Probably a lot of debate.

A couple of other technical points are also interesting here. First, the app still requires alarms to be set using the iPhone OS’s standalone Clock application. More importantly, it doesn’t require the Rise & Shine accessory in order to run—no different than any of the other hundred or more clock applications previously released in the App Store. It’s similar in this regard to Griffin’s recently-released iFM Radio Browser, which is also offered as a free download to accompany an accessory (Navigate) that’s neither strictly needed nor ideally designed to interface with the app. In both cases, the companies appear to have come up with the software and accessories at the same time, but due to the App Store’s vending model, they’ve charged higher than normal prices for the accessories and given away the software for free. This appears to be a simple way to have Apple take a 0% cut of the software rather than taking fees for both the software and the licensed accessory.

Will the “free app, expensive accessory” business model work going forward? Our suspicion is “probably not” in most cases, given both the low perceived value of iPhone OS apps at this stage, and the real challenge of convincing a user to make a subsequent hardware purchase after they’ve gotten an app for free, rather than having the hardware and software physically bundled together. The other option, having the software continue to be free, yet work only if it communicates with specific lock-out chips in the accessories, is surely in the midst of being tested right now—we’d expect Tom Tom and other companies to try this in the near future. Though this is going to create problems for other reasons, we’re just hoping that the results will be entirely unlike the accessory failures that plagued the WWDC 2009 demonstrations in June.

In any case, for now, Rise & Shine is an interesting example of the way the App Store currently operates, and developers are going to have all sorts of fun (cough, cough) experimenting with pricing and marketing strategies going forward. Let us know if you try the app and ultimately decide to pick up the Nightstand Charging Dock as a result.