By Anne Fisher, contributor

FORTUNE — Putting all or part of a company’s operations on the cloud — shorthand for large, remotely hosted data sets and applications — isn’t without risk, as recent outages and security lapses have shown. Still, cloud computing is so cost-effective that its popularity is growing by leaps and bounds.

In 2010, U.S. firms paid $21.5 billion to make the move to cloud services, a figure expected to balloon to $72.9 billion by 2015, according to a new study by IT research and advisory firm IDC.

Moreover, IDC predicts, four years from now cloud services will account for almost half (46%) of net new growth in overall IT spending in five key areas: applications, application development, systems infrastructure software, basic storage, and servers.

At first glance, the trend may look ominous for in-house tech staffers, some of whose duties are already being outsourced to cloud providers like Amazon (AMZN), Dropbox, Rackspace (RAX), and Terremark (acquired by Verizon (VZ) earlier this year).

In reality, though, the cloud won’t do away with jobs so much as it will change what skills employers need.

“The cloud doesn’t replace everything in-house tech people do now,” notes Aaron Hollobaugh, a vice president at cloud provider Hostway. “Besides, companies need people who understand how to manage migration to the cloud. There aren’t enough job candidates with the necessary skills right now.” The hottest specialty, he adds, is “hybrids, or connecting a company’s internal infrastructure with an external one.”

Bob Cuneo, CIO at tech staffing and consulting firm Eliassen Group, agrees. Starting last December, he says his company has seen “a double-digit increase in requests for systems administrators and network architects.

“Unemployment among IT professionals now is only about 3%, way lower than the national average,” he adds. “That’s partly because of the growth of the cloud. It’s allowing us to place many more people in jobs.”

A current trend he expects will continue: “Job losses [because of the cloud] are offset by job gains, first because many companies want to build and manage their own clouds, for security or compliance reasons, and they’ll need people with virtualization skills to do that.

“And second, they’ll need new hires with a broad range of skills, including project management and risk management, as opposed to pure IT.”

At the moment, Cuneo says, the right combinations of skills are hard to find. Ideally, candidates should have several different certifications. The six most in demand:

• VMWare Virtualization Certified Professional
• Cisco Certified Design Expert
• Licensed ZapThink Architect
• Open group IT Architect Certification
• Certified Information System Security Professional
• At least one of the cloud certifications available through CloudSchool.com

And that’s not all. To thrive in the new environment the cloud is creating, says Cuneo, “tech people need to be versatile and well-versed in broader business issues like corporate strategy and legal liability. They also need to be adept at collaborating with colleagues outside of IT.”

It’s a tall order. But, notes Aaron Hollobaugh, wearing several hats may also make for more interesting work. “For instance, moving to the cloud lets you concentrate on creating a better user experience for customers, instead of on the day-to-day nuts and bolts of maintaining the website,” he says. “It’s more about serving the company’s larger goals than about tech for tech’s sake.”