Intel (INTC) CEO Paul Otellini, with a more bullish call than many analysts, expects sales of PCs in 2009 to at least rival 2008. “My own bet is that we are likely to see unit (sales) flat to slightly up,” Otellini told analysts and developers gathered in San Francisco Tuesday morning for the annual Intel Developer’s Forum.

Otellini described that kind of resilience as astounding given the dismal economy.

“The PC market flat-to-up in the midst of the worst recession in 70 years shows that we have built something that is indispensable,” he said. The Intel boss also predicted resurgence in the computer market in the coming year. “We’ll see how 2010 plays out,” he said. Earlier this month, Goldman Sachs (GS) revised its forecast for PC unit sales to “roughly flat.” Analysts for the investment bank had previously predicted a 4% decline in PC unit sales.

Otellini’s remarks came at the beginning of three-days of geeking out by hardware and software engineers around all things Intel. What is clear, not just from remarks by Intel brass, but from the cross-section of people gathered for the developers’ event, is that the world that Intel encompasses is expanding dramatically beyond the PC. There were software people rubbing elbows with hardware purists alongside consumer electronics and mobile device folks.

Otellini made the point numerous times during his talk that Intel is moving from serving the personal computer industry, to serving the world of “personal computing.” That world includes more than desktop and notebook computers; it includes all sorts of consumer electronics gadgets that can fit in your pocket, your home, your office and your car.

Driving much of that growth, so far in the netbook category but eventually in smart phones, is Intel’s low-power Atom chip. Intel plans to put these chips and so-called system-on-chips into as many things as developers can think of uses for computing power. To help that effort along, Otellini announced an Atom developer’s platform, a framework of tools and software developer kits, which will allow developers to write an application once and have it work across multiple devices and operating systems running Atom chipsets.

Acer, Asus and Dell (DELL) announced they will support the framework, and you can expect applications for Atom devices to be sold in storefronts operated by these three PC makers (Intel is not getting into application sales business, its customers are).

Think of it as the first wave of app stores for Atom devices, in the same vein as Apple’s (AAPL)  app store for the iPhone and the iPod Touch. Otellini expects fun, consumer-tailored applications for netbooks first (translation: games and other time wasters), but expects a wide spectrum of applications eventually.

Expect to see the first application efforts in the next year-plus, Otellini says.