Strange but true: Despite the fact that unemployment is stuck at around 9%, which translates to about 15 million Americans out of work, nearly 3 million job openings in the U.S. are going unfilled, according to the Bureau of Labor Statistics. Why? The biggest reason is a mismatch between the qualifications employers are looking for and the skills job hunters have.

So which skills are most in demand? Here are 10 of the hottest:

1. Information technology. When career site Indeed.com recently analyzed millions of job postings on its web site, researchers found that the fastest-growing category of keywords — including HTML5, Android, mobile app, and social media — were in IT, and a new survey by tech job site Dice.com bears that out: About 65% of hiring managers said they hope to add tech staff in the first half of 2012. Roughly a quarter of those (27%) said they want to expand their IT headcount by more than 20%.

Openings for software developers who specialize in applications will rise by more than one-third (34%) by 2018, says Best Jobs for the 21st Century, a new book by job market analyst Laurence Shatkin, while companies will hire 20% more computer systems analysts. Rising pay in these fields reflects the surge in demand: The Bureau of Labor Statistics says that developers of systems software, for instance, earn an average of $94,180 per year.

2. Health care professionals. Partly due to the aging of the U.S. population, health care has been hot for a while now, and the trend shows no sign of slowing. Shatkin's research says the U.S. will need 103,900 more registered nurses every year (average salary: $64,690) well into the next decade, along with 7,860 new physical therapists per annum (average pay: $76,310). Demand for dental hygienists is up too, with a projected 36.1% growth in job openings between now and 2018 (average pay: $68,250).

3. Health care management and support staff. Don't have the training or experience to work directly with patients? No worries. "People often overlook the fact that businesspeople run health care companies," says Justin Hirsch, president of recruiting firm JobPlex. "With all the change happening in the system now, there is churn as well as growth. We're constantly seeing new openings in general management, finance, marketing, human resources, you name it."

4. Engineers. Note to college students who want their pick of job offers when they graduate: Consider majoring in engineering. A whopping 88% of employers in a new poll by the Society for Human Resource Management bemoaned the difficulty of finding enough engineers to hire. Civil engineers are in demand too: Shatkin's analysis of BLS data shows a 24.3% spike ahead in jobs for people who design roads, bridges, and other infrastructure projects (average annual pay: $77,560).

5. Industrial skills. Think U.S. manufacturing is moribund? Think again. More than two-thirds (68%) of employers in the SHRM survey pointed to a shortage of qualified new hires to replace people retiring from the skilled trades: electricians, carpenters, welders. Moreover, says Justin Hirsch, "We're seeing an increase in industrial hiring in logistics, supply-chain management, and plant management." As more companies go global, demand for expertise in logistics — the art and science of moving stuff efficiently from one place to another — will continue to heat up.

6. Life sciences and biotech. Medical innovators ranging in size from Big Pharma down to biotech startups are on a hiring binge: Shatkin sees a 40% jump in job openings for research scientists between now and 2018 (average salary: $76,700). As with health care companies in general, these employers will also need managers and support staff (see No. 3).

7. Salespeople. Selling has historically been the closest thing there is to a recession-proof career, and this economic downturn is no exception. Since they're the ones bringing the dough in the door, salespeople are often the first to be hired and last to get laid off. Almost three-quarters (72%) of employers in the SHRM survey said they can't get enough salespeople now.

8. Accounting and finance. Demand for accountants and finance mavens (particularly forensic accountants and compliance specialists) has been climbing steadily for the past several years, and U.S. colleges are still not turning out enough grads in these fields to fill the available openings. The SHRM survey found that more than half (54%) of employers would hire more accountants and finance experts if they could find them.

9. Discount retailers. "Not to mention any specific company names -- everyone knows who they are, anyway — but the big national discount store companies have flourished during this recession," notes Justin Hirsch. "And most of them are hiring managers as well as in-store personnel."

10. Private equity firms. Recruiters report that private equity firms are actively seeking management talent for their portfolio companies "across all industries and all functional areas," says Hirsch. "They're poaching already-employed, seasoned managers from big companies — people who can step into either a turnaround situation or a pre-IPO company and make it work. These are challenging jobs, and could be a real feather in a manager's cap if he or she can bring it off successfully."

Do unemployed executives have a shot? "With the right network, yes," Hirsch says. "It's about having great business acumen, especially a knack for coping with ambiguity, and being known for that. It helps to have the right connections."