It’s one thing to design and build software to live in the cloud from scratch. It’s something else to move existing applications over to cloud-computing platforms, which many companies need to do. This often means completely rewriting parts of the code to make it compatible with a particular provider’s infrastructure. CloudSwitch, a startup based in Burlington, MA, has designed software that could make the transition almost as simple as dragging and dropping a file from one folder to another.

CloudSwitch offers software that acts as an intermediary layer between a cloud provider and a company’s applications. The software is installed at the company’s data center, and it handles the tricky task of transferring applications over to the cloud provider’s platform. The only catch is that customers must already use virtualization software–commonly used to make data centers more efficient by simulating multiple “virtual machines.”

Ellen Rubin, founder and vice president of products for CloudSwitch, explains that CloudSwitch’s software grabs information about the virtual machines running an application. It then runs a “cloud-fitting” algorithm that compares how the application works in the data center to how it would fit into the cloud provider’s infrastructure. Finally, CloudSwitch’s software translates commands between the two systems.

CloudSwitch Explorer, released as beta software last week, is a free version of the product. After downloading and installing it in a corporate data center, an administrator can move five Windows or Linux virtual machines into Amazon’s Elastic Compute Cloud, and then manage them as if they were still running locally. The company hopes that giving users a chance to try out the software this way will encourage them to buy the enterprise product, which allows for more users and more virtual machines, and will be available later this year. CloudSwitch also plans to add support for other cloud providers as it goes forward.

The company has attracted roughly $15.5 million in venture-capital funding from Matrix Ventures, Atlas Ventures, and Commonwealth Capital Ventures.

CloudSwitch is “quite an interesting company,” says Reuven Cohen, the founder of the Cloud Computing Interoperability Forum, a group that works to facilitate standards for cloud computing. Cohen, who is also the founder of a Toronto-based cloud-computing company called Enomaly, says he’s particularly interested in the claim that the technology requires no configuration for companies trying to move into the cloud. “If it lives up to the hype, it would be really cool,” he says. Cohen says there’s already tremendous demand for services that help companies move their applications into the cloud. He notes that many companies are interested but haven’t yet made the switch.

Cohen adds that cloud-computing providers have little incentive to provide the kind of service that CloudSwitch is offering. “Easy in means easy out,” he says. “The last thing these guys want is for you to easily leave.” A third-party service, on the other hand, can offer a product that makes it easy for companies to switch from one provider to another.

“Moving to the cloud is still not for the technologically faint-hearted,” agrees William Fellows, a principal analyst with the 451 Group, a research firm based in New York. Many cloud providers are focused on hardware and infrastructure, he adds, and they don’t have the software expertise needed to help customers transfer applications.

Fellows says a long-term opportunity for CloudSwitch could lie in enabling companies to switch between different cloud providers depending on the needs of different computing jobs. Companies might want some tasks to be processed by a cloud provider with data centers in a certain geographical location, for example, while other tasks might need to be scheduled based on the cheapest available price. Normally, it would be too difficult to move from one provider to another this way, but Fellows thinks CloudSwitch’s technology could change this, if it works as promised.