On the horizon is cloud computing, which also holds the promise of reducing corporate IT overhead but requires more up-front spending than outsourcing.

"Over the longer term, we're pretty bullish about cloud computing," IDC's Minton said. "But there will be a lot of hurdles for a bigger corporation. It's difficult for them psychologically to give up control, and there are quite a lot of up-front costs to engage consultants, to roll out applications to a large number of employees, and there's training involved. But ultimately these projects save money."