Because Windows 8 is still in a test version -- Release Preview -- it is possible that applications built now will have to be modified to take into account any changes made to the OS between now and then, but the modifications wouldn't be major, according to a Microsoft official.

"We only have one more milestone left for Windows 8 -- the RTM [Release to Manufacturing] -- so there's the potential that there may be some changes you'd need to make to match the final version," said Jason Zander, corporate vice president for the Visual Studio team in the Developer Division at Microsoft.

"But we're not making a ton of breaking changes, so it's a good time to start building applications for the environment. We're not 100 percent close, but we're getting pretty close," he said during an interview at the TechEd North America conference.

It's critical for Microsoft to generate enthusiasm among developers, especially commercial developers, so that at launch Windows 8 will have a healthy number and variety of applications built for the new Metro user interface, which has been designed for the touch-based screens so popular in tablets. The Metro interface will also work in desktops and laptops used with keyboards and mice.

According to Zander, momentum is picking up. "We're seeing good takeup already. You've got some applications already built into the Release Preview, which isn't even the final release of the product. We're seeing a lot of people pick up those tools and starting to build applications," he said.