If you need to create or edit the occasional Word doc, Excel sheet, or PowerPoint presentation on your iPad, OnLive Desktop is a app that provides a virtual Windows 7 PC. The app is free, and it does not require any previous Microsoft purchases or licenses to use Word, Excel, or PowerPoint. With each free account comes 2GB of storage on OnLive's servers.
OnLive just released OnLive Desktop Plus, which adds Internet Explorer to the mix, along with priority access when tunneling into OnLive Desktop. The free account delivers access "as available," and I was occasionally denied access before I upgraded to the Plus account.
Before you can use the app, you first need to sign up for an OnLive account from a computer or via Safari on your iPad. You'll need to sign in to your account each time you launch the OnLive Desktop app.
Launch the app and you'll see a sparse yet familiar Windows 7 desktop. On the desktop are icons for Word, Excel, PowerPoint, Internet Explorer. A shortcut titled Documents is where you can save and open files to and from your free 2GB of online storage. Along the bottom of the screen is the Windows 7 menu bar with shortcuts to the three Office apps, IE, the keyboard, Surface Collage, Paint, sticky notes, and the calculator. Windows Media Player is on board for playing music or video files, and Windows Photo Viewer takes care of your photo-viewing needs. You can't install any new applications, you can't change the wallpaper, and you won't find standard Windows items such as the Control Panel.
Also, you can't use the standard iPad onscreen keyboard but must settle for the Windows onscreen keyboard, which I find isn't nearly as easy to use. To improve the Windows onscreen keyboard, I suggest you trade out the default Float setting, which gives you a small keyboard you can drag around the screen. Tap the Tools menu option at the top of the keyboard and then choose Docking > Dock at the bottom of the screen. This will give you a keyboard that runs from edge to edge, with slightly larger keys than the floating keyboard.
Upgrading to OnLive Desktop Plus is not treated as an in-app purchase; instead, you must subscribe on OnLive's Web site. After you purchase the Plus plan, you'll be able to use IE to browse the Web from within the OnLive Desktop app. Tabbed browsing is supported, as is Flash, which might be reason alone to use IE instead of Safari at times. For example, you can watch free Hulu videos with IE, which is something you can't do with Safari.
Use an Android tablet? Then read Ed Rhee's tutorial about how to get started with OnLive Desktop for Android tablets.