Tom Clement has reinvented his career before. In 1984, he realized working in technology would suit him better than his job as a litigator in Texas. "I came home one day from work, and I was used to being really tense," he says. "But that day, my secretary's recorder had broke. I'd taken it apart, put it back together, and somehow, it worked. I was whistling and in a good mood because of it, and my girlfriend heard me and said, 'Tom, maybe you were made for a different line of work.'"

After moving to California and taking a night class at UC Berkeley in C-Programming, he put his law ambitions aside and took a job at a C-compiler company, taking pieces of code and translating it into a language that could work on Motorola hardware.

Today, Clement, a journeyman in software development, might be facing a bigger career test: the movement of software to the Web and the effect it will have on developers like himself and the thousands of IT support and maintenance pros taking care of traditional software at small and large enterprises across all industries.

Software as a service (SaaS), one flavor of today's hot buzzword, cloud computing, refers to applications that users access over the Web and which live on physical servers hosted by the software vendors or a third-party, not servers owned and cared for by an in-house IT department.

"I've got some learning to do in my 50s," Clement says. "Now, I need to know more about Web 2.0 and java programming. While I know I can, I still have that fear of, 'will I be able to do it?'"

Clement, now senior developer at Serena Software, in some ways is already adapting, as his company has begun building SaaS applications along side its traditional software. And sure, developers have been through big transitions in computing before, most notably the move from mainframe computers to the PC era.

The IT industry is now preparing for a new round of upheaval as a result of SaaS adoption of offerings from the likes of Google (with its Google Apps) and Salesforce.com that let users run applications via the Internet. Zoho, a SaaS vendor that does most of its development work in India, has also sold a plethora of applications, including in staple, Microsoft-dominated areas like word processing, spreadsheets and presentations.