The very first time we spoke to OnLive CEO Steve Perlman, we asked him: why video games? He told us that virtual worlds were the ultimate test of a cloud streaming service. If OnLive could deliver playable games across a home internet connection despite latency limitations, it could stream just about anything. Just over a year ago, he showed off that "anything" on the D8 stage, streaming Windows 7 to an iPad and manipulating PC apps from the touchscreen.

Starting this Thursday, you can get a taste of the same. OnLive is launching a virtual desktop service in the cloud this week, to compete with the likes of Citrix, VMWare and Wyse, but unlike will those providers, you don't need to set up host servers or have a corporate infrastructure to join. You know how OnLive streams compressed video frames from virtual gaming PCs in order to power its cloud-based games? Today, the company's basically just removing the gaming layer, exposing the Windows 7 experience underneath. That means all you need is an iPad (Android, Mac and PC apps are on the way) and a fast Wi-Fi connection to have a mobile Windows 7 office with a touchscreen... and the basic service is completely free. You can sign up today, and download the app from the iTunes App Store, set up an account and get started on Thursday. OnLive told us the app's already approved by Apple and ready to publish, but the company wants to know how many servers to allot to match expectations.

How is it possible for OnLive to offer this for free? Well, OnLive Cloud Desktop will offer three tiers of service, and what you're getting gratis is pretty basic, really. It a locked-down copy of Windows 7 with Microsoft Office and the Windows 7 Touch Pack pre-installed, just enough to get your feet wet editing documents and playing with multitouch. The free version basically gives you a timeshare on the company's servers, and it won't hold onto your session, but you do get 2GB of cloud storage which conveniently acts like Windows 7's Documents folder (it'll also be accessible from the web) and OnLive will automatically save your documents there.

Where it gets interesting is with the company's Cloud Desktop Pro plan, which won't be ready at launch: for $9.99 a month, OnLive promises it will save you a dedicated spot, give you a cloud-accelerated web browser and 50GB of storage, and let you install apps of your own. The method by which you'll be adding your own programs is still up in the air, though, and they might have to be pre-approved; Perlman explained that his company's worried about the unknown impact certain apps could have on the service, and will ramp up self-installs slowly. OnLive's also planning enterprise tier of service if you want to outfit your whole company with MicroConsoles (yes, that tiny ARM box will be a capable thin client, too) and need to have IT control over permissions. There's also a "collaborative services" package which adds voice chat, screen sharing (based on the game service's Arena game spectating) and even cooperative control over a single session by multiple simultaneous users.

We haven't spent as much time as we'd like with the Cloud Desktop yet, but we did give it a try at OnLive's HQ and while there's a little bit of perceptible lag, it's pretty impressive manipulating objects with our fingers and flipping through PowerPoint presentations on a desktop miles away.

Update: Looks like the app is coming Friday instead of Thursday: "Although we had planned to go live on Thursday, Jan 12, we've had such a large influx of signups, we are taking another day to deploy more servers to handle the load, and we expect to go live on Friday, Jan 13," OnLive tells us.