Apple (NASDAQ: AAPL) stock holders shouldn’t be surprised, but many analysts think the iPad is killing the PC. The tablet was considered a decent threat in 2010, but since the iPad 2 came out in March it has only grown in dominance. Among those feeling the burn most are makers of notebook PCs and ultra-small “netbooks.” This includes Hewlett-Packard (NYSE: HPQ) and Dell (NASDAQ: DELL).

The notebook computer market was growing by leaps and bounds across the past three years before the technology’s ascent ran into a brick wall — well, actually ran into Apple iPad tablet sales. Research group Canalys said that even though it expects the notebook PC category to grow by around 8% this year, every ten tablets sold will mean five notebooks that don’t.

So will the iPad kill notebooks, or can they coexist? For what it’s worth, companies like Hewlett-Packard (NYSE: HPQ) and Dell (NASDAQ: DELL), believe the cheap computers have a place and are developing new models to connect with consumers… At least in the short term.

Hewlett-Packard is rolling out a major iPad competitor with its new Palm-made TouchPad tablet, but the company is also driving forward with its notebook business. It announced three new models of the HP ProBook 5330m, HP Mini, and HP EliteBook 2560 notebooks, alongside a new wireless Internet service to make the portable PCs more appealing to frequently traveling professionals.

That new service, dubbed HP DataPass, will let HP notebook users purchase small access times to a 3G connection through Sprint (NYSE: S), rather than using a WiFi connection or subscribe to an expensive and permanent data plan with that telecom or others like Verizon (NYSE: VZ) or AT&T (NYSE: T). DataPass is the heart of HP’s strategy to keep the notebook not just alive but thriving, making infrequent but reliable service as much a selling point as portability for the product line.

HP will need to do more though. Before too much time passes, it will need to find a way to lower the price on its newest notebooks. At $799 and $1099 for the basic new ProBook and Elitebook notebooks, HP’s devices make Apple’s tablet look affordable by comparison, even with the extra cost of a 3G dataplan through Verizon or AT&T factored in.

The only thing that will make these devices appealing to professionals in the long term is the broadest service and the lowest possible price, and undercutting Apple will be the only way to get that message across. (That pricing structure also has to extend beyond the simplest version of the hardware, like the aforementioned HP Mini.)

HP also needs to find ways to make apps a central feature for its notebook business. The company’s is pouring money into developing its own app store for the TouchPad tablet that will run on the new WebOS 3 operating system. The company’s notebooks need to benefit from this R&D as well if the segment is to grow.

PC manufacturers like Dell (NASDAQ: DELL), Lenovo and Acer are all in the same boat as Hewlett-Packard. Those companies are also focusing on notebooks as their own tablets have borne mixed results. If they employ the aforementioned strategies, will the notebook PC market rebound and begin growing again? Possibly.

On one hand, Canalys said that it expects the notebook market to grow 8% by the end of 2011. Unfortunately, estimates are that it will tail off quickly after that. If the notebook technology can get cheap enough and offer compelling tools for doing business—even as simple a thing as a better keyboard is a selling point over a tablet—and it can exist side by side with tablets. But the window of opportunity is small.

The key for these manufacturers will be to mix the two, making an affordable tablet that can dock in a small adapter that gives it the same tools as a notebook. With that technology still being years away from affordability though, notebook makers can find safety in low cost, service, and good app support.

As of this writing, Anthony John Agnello did not own a position in any of the stocks named here. Follow him on Twitter at @ajohnagnello and become a fan of InvestorPlace on Facebook.