I thought the apps gold rush - which saw bright young developers making thousands from software developed in their bedrooms - might be over, with the big boys moving in to crowd them out.

It seems not - I've been hearing the stories of two British teenagers who've made small fortunes from smart ideas.

One is making money despite being barred from Apple's App Store; the other has hit the jackpot because Apple has chosen his game as its App of the Week.

My first example, Greg Hughes, is a 19-year-old computer-science student at Birmingham University. Software development has been a hobby for a while, and he works for a web design firm when he's not studying.

A while back, he came up with a way of synchronising his iPhone to his computer over a wireless network; as things currently stand, you have to plug the phone in.

After paying the £60 fee for Apple's iPhone software development kit, he turned his idea into an app and submitted it for approval.

Greg admits that he never really expected the wi-fi sync app to be approved because, in effect, he was messing with Apple's own technology.

"I thought it was a bit of a grey area. It doesn't break specific rules, but it's something that Apple would prefer to do themselves."

What surprised him was that, rather than just a flat rejection, he got a phone call from a man at Apple's California headquarters:

"He indicated to me that there was no way it would ever be accepted. But he was very complimentary about the app - he told me the iPhone team had been impressed, and asked me to send my CV when I graduated."

All very well - but no reward for Greg's hard work. There was, however, another market for his app, albeit one with far less traffic and therefore less lucrative for developers. There are plenty of users with so-called "jail-broken" iPhones, which means they can install apps that don't need to be approved by Apple.

The young developer decided last week to place his app in a marketplace for indie apps at $9.99 - quite a chunky price - and see what happened.

The result? In just 72 hours, 2,500 people bought it. So Mr Hughes has been able to make over $20,000 in a few days, even without the backing of Apple. You'd think he'd be over the moon. But he reckons he could have been a millionaire if he had managed to get wi-fi sync into the App Store.

"I accept they are a business and they answer to their shareholders," he told me. "But they are stifling innovation. It's not a good sign for the industry as a whole."

My second case study has no complaint about Apple, even though his app first made a splash on Microsoft's Xbox platform.

Edward Bentley, another teenage student, started a few years back by making some online games using Flash, but none caught on and he got bored and gave up. Last autumn, he started working with Microsoft's free Visual Studio sofware to make a game for the Xbox Live games platform.

By November, he was ready to submit The Impossible Game - a simple but compelling game involving jumping a cube over a series of obstacles - to the Xbox Indie marketplace.

Unlike Apple's App Store, this outlet has no corporate gatekeeper - the games are reviewed and rated by the community. Edward's game got through the process, and he then had to choose a price. Users pay in Microsoft points, and he went for the lowest price, 80 points, equivalent to $1.

The game was an instant hit, with a few hundred sales most days in November and December, and then a surge of sales after Christmas, as Xbox players used the points they'd been given as gifts.

Edward was cagey about giving me exact numbers but I got the impression that over the space of a few months, sales had hit five figures, and at a dollar a download, that's a sizeable amount of cash for a teenager.

But that was just the start. Edward, who'd previously always coded on a PC before, spent some of his earnings on a Mac mini and set about creating an iPhone version of The Impossible Game.

"You have to start from scratch," he told me. "It's a completely different language. You have to get everything pixel perfect, and as it's on a small screen you have to rework everything."

So it took a while but when he submitted the game to the App Store in mid-April, it took just seven days to get through the process and into the store. This time, he decided on a marketing plan, setting up a website to promote the game and sending it to reviewers with a request to publish on 30 April.

This was a total failure - the reviews dribbled out, hits on the website were meagre, and it seemed the game might disappear without trace.

But a few days later, it was featured in the "new and noteworthy" section of the US App Store, and began to take off, making it into the Top 10.

Then, a week ago, the phone rang: "I got a call from Apple in California," says Edward. "They said we want to do some promotion for the game."

The promotion Apple had in mind was making The Impossible Game its "App of The Week". So right now, millions of iPhone and iPod Touch users who take a look at the United States App Store see a banner ad for the game. "It's the kind of advertising that money couldn't buy," says Edward.

When I last looked, Edward's game was at number four in the US chart, so he's done what many British stars have failed to achieve - he's made it big in America.

He's still very coy about what that means in terms of sales and cash, but I've had a look at the sales of apps which have had similar chart positions and I think it's safe to say that university tuition fees are not going to be a worry.

So, we have two smart young self-taught developers who have found that in the new app economy they can compete with software giants and win. They may turn out to be one-hit wonders. But both Greg and Edward are now planning to develop more apps, and their success may inspire others to try their hand.

