Bill Atkinson, a Silicon Valley software savant, is back in the game.

The man who helped develop the original Macintosh has been gone for a while, concentrating for the past 15 years on his rich and vivid nature photos. But there I was recently talking with Atkinson at his house on a hill in Portola Valley about his latest software creation -- an iPhone app that lets you design and send an honest-to-god, snail-mail postcard from your mobile device.

"I thought, 'Well, how hard could it be to write an iPhone app?' " says Atkinson, 59. "It was harder than I thought -- by quite a bit."

But it was worth every trial and error and error message. After two years of work, he and his wife, Sioux, released PhotoCard, an app that they believe will help people connect with each other in ways that are fast fading.

"It's about a tangible artifact and a lasting memory," Atkinson says of his postcards, "neither of which we're getting with our e-mails, texts, phone calls or Facebook or Twitter."

But sitting with Bill and Sioux Atkinson at their kitchen table, it's hard not to think that maybe it's about more than that. PhotoCard was a chance for Bill Atkinson to work with the love of his life on a project that combined two art forms -- photography and programming -- to which he's dedicated himself.

And the app represents the logical extension of an audacious vision he and others began work on 20 years ago with the launch of General Magic, a Silicon Valley startup that shone brilliantly and briefly before going the way of a company before its time.

General Magic came up with software for a personal communicator that would serve as calendar, memo pad and an e-mail device. It relied on radio waves to send "telecards," messages including text, sound and animations. It is the telecards feature that Atkinson says his postcard app most closely resembles.

"We thought of them as digital postcards," Atkinson says of the 1990 vision. "We couldn't really make that happen 20 years ago.''

In fact, it was after his General Magic experience that Atkinson said he was burned out on programming and that he doubted whether he would ever work as a software programmer again. But today, the $4.99 PhotoCard app allows iPhone, iPad and iPod touch users to select from 150 of Atkinson's nature photos or to use their own photos to create postcards. Once the person sending the card types a message, it can be sent in virtual form to an e-mail address (in a nod to telecards, senders can add an audio message) or in real form to a postal address. Digital cards are free. Real cards cost $1.50 to $2 to send.

The delivery process is its own bit of engineering. The postcards are uploaded to a server. Atkinson provides quality control through a system that is becoming increasingly automated. He ships them digitally to a printer in Santa Clara, who prints hundreds of cards at a time. Then the printer drives the cards to San Jose's main post office where they are mailed out using special postage that allows them to bypass sorting machines that can bend, fold and mutilate.

True, PhotoCard pales in comparison to Atkinson's earlier achievements like HyperCard, a groundbreaking software tool that allows novices to create programs and work in multimedia. But Atkinson is clearly thrilled with what he's done.

And those who know his work are thrilled for him. Andy Hertzfeld, a friend and colleague at Apple and General Magic, says Atkinson's programming legacy has long been established.

"He was the key person behind the Mac user interface," Hertzfeld says, "which made, for the very first time, computers accessible for ordinary people -- which was a monumental achievement."

Now Hertzfeld is happy to see his friend taking such joy in his latest creation.

So far, the joy must serve as the return on investment in PhotoCard, which launched late last year. With about 35,000 users, the app is not profitable, Atkinson says. He says he is struggling to be heard above the noise created by a market of 300,000 apps clamoring for attention. It's a change from his Apple days, when the company would ship his programs and the computers they ran on to millions around the world.

"Being an app developer isn't at all like working at Apple," Atkinson says. "There is this huge haystack of apps and even a very shiny needle can get lost in that haystack."

Here's hoping a few more spot the glimmer.

Shoot! I thought you were the Head Jack@ss!