At a time when technology is changing everything, continuous learning is essential to staying competitive in the job market. Whether you’re a recent graduate, a job seeker or a CEO, if you’re not learning, you’re falling behind. 

Here’s the good news: new models in online education are rapidly disrupting the concept of ‘learning’ as we know it, and the tools you need to update your skills are now just a click away. We’re not talking about online college – a costly, time-consuming investment in pursuit of a degree – but rather free or low-cost, 100% online access to learning anything. We’re talking about MOOCs.

From specific skill sets to entire courses through respected universities, massive open online courses, or MOOCs, are reshaping the way we learn. It’s a familiar process: simply enroll in a class, complete the term requirements, and receive a certificate from the accrediting university at the end. Except that with MOOCs, you don’t have to be a student, you don’t have to pay any money, and you can quit at any time.

Elite professors from Harvard, MIT, Stanford, Princeton, Brown, Duke and Columbia have already signed on.  Imagine how much more interesting your resume could be with a few of these certificates tacked on:

Unsure how you’d make time to fit a college course into your busy schedule? The best part about these emerging e-learning platforms is the complete and utter flexibility. Want to be more effective in Excel? Or learn the basics of search engine marketing? A lunch hour or two spent interacting online will do you.

If you’re a job-seeker, this should be particularly exciting news. You have the time and opportunity to instantly better your offer. But it’s equally important for everyone else, too. At any level, online education opportunities enable professionals to improve their skills, gain confidence, advance their careers and make themselves more marketable to employers.

Here are a few of our favorite e-learning sites for professionals. Where will you begin?

edX & Coursera

What: edX is a not-for-profit venture of Harvard and MIT offering free online courses to students worldwide. Coursera is a social entrepreneurship company offering the same services through the likes of Stanford, Penn and UC Irvine.

Who:“Anyone, anywhere, anytime.” Note: coursework completion is required to receive a certificate.

How: Many courses have already started for the fall semester but accept students on a rolling basis. Select a course, enter your email, and you’re enrolled. It’s that simple.

Khan Academy

What: A “global classroom” with educational videos and practice materials ranging from basic computer programming to SAT prep.

Who: Ages 2-92. Though less professionally-minded than some other sites, Khan Academy offers invaluable explanations of topical issues too, such as The Greek Debt Crisis.

How: Enter your email.

Lynda.com

What: Extensive software, creativity and business training video tutorials for professionals.

Who: All levels of expertise in business, tech, marketing and design. Topics are as specific as “Illustrator CS6 New Features” and as general as “Acing Your Interview.”

How: Get started anytime. If you’re an individual (schools and companies can subscribe, too), it’ll set you back $25/month with no annual contract. But with more than 82,000 video and interactive tutorials, Lynda.com is worth its salt.