WASHINGTON — Todd Moore didn't foresee that he was about to embark on a new career when he bought his first Mac last year. It just sort of happened.

Moore, 35, of Sterling, Va., had been spending his working life pulling down six figures as a network security professional — a job he liked well enough. But after reading a few get-rich-quick stories about programmers making good money from selling applications designed to run on the iPhone or iPod Touch, he decided to give it a go. How hard could it be?

Learning the tricks of iPhone development in his spare time, Moore rolled out a handful of applications and posted them for sale on Apple's App Store. Some went nowhere, sales-wise, but a couple have hit the big time.

The biggest success, so far: White Noise, a $1 program that generates soothing sounds for people who have a hard time getting to sleep. Card Counter, a $3 application designed to help users learn the principles of counting cards to win at blackjack, has also been a brisk seller. Last month, on the software sales-tracking charts at iTunes, both programs appeared on the "top 20" most-purchased list.

That's about the time Moore gave his two weeks' notice and decided to pursue this dream full time.

"In one week, I made what I would've made in four months," he said. "That's when I decided to pull the trigger."

Apple's online software shop has given rise to a new set of entrepreneurial programmers such as Moore, hoping to make a living, or a bit of supplemental income, by dreaming up software products that will prompt iPhone users to part with a buck or two.

Jumping into this area requires a bit of programming knowledge — even experienced programmers say it takes a few weeks to master the ins and outs of developing software for the device. But thanks to the App Store, which pays developers 70 percent of the sale price, an application by an inspired programmer such as Moore has as much chance of making it big as an iPhone game designed by a team at, say, Electronic Arts.

Another programmer, Keith Shepherd, gave up his job as a developer of health-care software last year to start his one-man iPhone game shop, Imangi Studios, out of his Washington apartment.

So far, Shepherd has released a pair of well-reviewed word puzzle games, Imangi and Imangi Word Squares. Last month, he released his latest game, Little Red Sled, in which players tilt their iPhones left or right to steer a sled down a series of snowy hills. He's not making as much as he did at the job he left, "but I'm getting there," he said.

Even for folks who are keeping their day jobs, there's a sort of do-it-yourself excitement to building applications for the iPhone (and the iPod Touch). There's a gold rush mentality out there, but some say they just like the chance to dream up something and execute it by themselves, without having to work with a huge development team or a big budget.