Today, Microsoft took yet another step to advance its Windows Live SkyDrive consumer-oriented cloud service, offering up free mobile apps for both Windows Phone and Apple's iPhone. I've been using these apps for over a week, and the capabilities are impressive, especially on Windows Phone, which provides document editing capabilities in addition to viewing.

Yes, Virginia, Microsoft is serious about the cloud.

Each app looks and works similarly, though within the confines of the UIs styles of the two mobile platforms. On Windows Phone, this means a Metro-style UI with various screens, or panels, of information, and a bottom-mounted command bar for accessing Settings, changing the view style, and refreshing the view. On iOS, this means a bottom-mounted tab bar which you can use to switch between various screens of information and a Settings interface.

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The main SkyDrive view in Windows Phone (left) and iPhone (right)

In each app, the following screens are available.

Files. The stock view, which amounts to what you see when you navigate to SkyDrive from your PC's web browser. This includes any files and folders found in the root of your SkyDrive storage.

Recent. A list of recently-used documents, with the most-recently used document at the top. This view is consistent between apps so that the most recently used document is always on the top, no matter where you accessed it from (the PC, the web, a mobile app).

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Recent view (iPhone)

Shared. A list of the files and folders you are sharing with others.In my case, this includes the Windows Weekly folder (which I share with Mary Jo Foley and others at TWiT), the Windows 8 Secrets folder (which I share with Rafael Rivera), and others.

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Shared view (iPhone)

As noted previously, there's also a Settings interface in both apps, but there's not much there. You can configure which account to use--offering the ability on Windows Phone for the first time to sign-in with one "main" Windows Live ID on the phone but a secondary Windows Live account for SkyDrive--and then some "About" information. That's it.

Of course, you're not here to view lists of files and folders. The reason one might want a SkyDrive mobile app is to access your cloud-based files on the go. This can be for reading purposes or for light editing. The experience is similar on both platforms but different in one crucial way.

On the iPhone, you can easily view Word documents, Excel spreadsheets, PowerPoint presentations, PDF files, text files, and web documents using the built-in viewer utilities provided on that platform. (These utilities typically surface in the Mail app, such as when you try to open an email attachment.) You can also view photos and then download them to the phone, one at a time.

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Viewing an Excel spreadsheet on the iPhone

Curiously, you can't do a thing with OneNote notebooks, and that's true even if you've installed Microsoft's iOS version of OneNote. I suspect that will be changing in the future, but for now, when you select a OneNote notebook, you simply get to view an informational screen about the file. There's no download or view option.

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There's no OneNote viewing or editing on the iPhone, curiously

Windows Phone offers a more complete experience, as you might expect.

As with the iOS app, the Windows Phone version of SkyDrive lets you view Word documents, Excel spreadsheets, PowerPoint presentations, PDF files, text files, and web documents, and OneNote notebooks too. But in the case of Word, Excel, PowerPoint, and OneNote documents, they're opened in the appropriate Office Mobile 2010 app, and not in a simple viewer. So you can edit them too, if you'd like, save them to the phone, share them with others, and so on. It's a pretty powerful capability.

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Windows Phone can view and edit common Office file types, including OneNote notebooks

Ditto for other file types. PDF files open in Adobe PDF Reader, and if you don't have that app, you'll be prompted to download it from the Windows Phone Marketplace. Text files open in Word Mobile, giving you all of the editing, saving, and sharing functionality you'd get with a Word document. And photos can be viewed and downloaded, one at a time, as in iOS.

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Photo thumbnails (Windows Phone)

Final thoughts

Microsoft has been busy lately buttressing its mobile and cloud computing apps for consumers, and that's true on both Windows Phone and, surprisingly, on iOS as well. Two weeks ago, SkyDrive seemed like it had stalled in the face of Apple's grander ambitions with iCloud. But today I'm not so sure: If you're a Windows Phone user, SkyDrive has become a no-brainer, and even on the iPhone, where most users are also Windows desktop PC users, SkyDrive suddenly makes plenty of sense. And since both of these are apps are free, you should check them out, regardless of which mobile platform you've chosen. Which raises the only downside to this equation I can find. Where the heck is an Android version of this app?

Download SkyDrive for Windows Phone (soon)
Download SkyDrive for iPhone