As more and more companies turn to Linux for mission-critical operations, making sure IT staff have the necessary skills is becoming more important than ever.

That's a significant challenge, because demand for Linux skills now far outstrips supply, making them a particularly hot commodity in the hiring market as companies large and small struggle to equip themselves with the talent they need.

The Linux Foundation reports that skills are one of the top challenges named by companies already using Linux, as I've noted before, while on IT employment site Dice.com, demand for Linux experience is growing at a rate of 31 percent year over year as opposed to just 20 percent overall.

So how do IT professionals get these coveted skills, whether for their own job-hunting purposes or for an employer that needs them? There are numerous opportunities online.

1. PaulPaulito.com

One new site that just launched earlier this year is PaulPaulito.com, which is based in the Netherlands but offers a whole series of online screencast training videos in English, Spanish, and German. The company is a training partner approved by the Linux Professional Institute (LPI), and it offers courses designed to help prepare for LPI certification exams. The first one, for example, targets the LPI-101 exam with a series of 45 10-minute video modules available for streaming; practice exams are also available. Subscription plans begin at 49 euros, or about $67, per month, and can be canceled any time.

2. LPI Partners

Speaking of LPI, the certification organization itself has also established partnerships with numerous other training partners around the globe. A regional lookup guide on the LPI site lets you search for training partners near you.

3. Red Hat

Linux vendor Red Hat is another source of training and certification programs, including several online offerings geared toward Red Hat Enterprise Linux. Virtual courses include Red Hat system administration and Red Hat Linux troubleshooting, with prices starting at $1,400.

4. BeginLinux.com

A variety of self-directed online courses are available at BeginLinux.com, focusing on topics including Ubuntu Server, Apache Security, and CentOS Server. Pricing starts at $95.95.

5. The Linux Foundation

Similarly, the Linux Foundation also offers an array of online training courses in addition to those it delivers in the classroom. Embedded Linux, the Linux Kernel, and Open Source Compliance are all part of its lengthy list of offerings. Courses are delivered using a live audio conference bridge and a live Java-based virtual collaboration tool. A search tool on the Linux Foundation's site can help you find one you're interested in. Pricing for virtual classes is $2,750.

6. Canonical

Those seeking skills in Ubuntu can also find online offerings through the Ubuntu site, which offers numerous courses through its training section.

7. IBM

IBM is another vendor that offers its own Linux training classes, including several self-paced online offerings. Online pricing starts at $675.

8. LinuxCertified

Among many onsite learning opportunities at LinuxCertified are also several distance learning options, including Linux fundamentals for $99.

9. The Free Technology Academy

I've already written about the Free Technology Academy's online Master's Program in Free Software and Free Standards, offered in partnership with the Free Software Foundation, but the organization also offers numerous online courses in Linux and other free technologies. Pricing per course module is 380 euros, or about $517.

10. Novell OpenCourseWare

Much like Canonical, Red Hat, and IBM, Novell offers a variety of training courses in using its Linux products. Training is free, and there's no registration required.

11. The Virtual Training Company

The Virtual Training Company offers a broad series of Linux tutorials online, as I've noted before, and some of the content is free. Tutorials require either Flash or QuickTime. A monthly subscription price of $30 for individual users gets you access to more than 900 courses on the site, including the complete content for those focusing on Linux.

12. E-Learning Center

Similar to PaulPaulito.com, the E-Learning Center offers courses focused on preparing for LPI certification as well as comparable offerings for Red Hat certification. Either way, a year's access costs $69.

There are, of course, numerous other offerings out there as well. Wherever you choose to go, however, you'll be on the way to gaining fresh Linux skills.