Most remote workers don't have an "IT Guy" or an assistant on hand, so it's important to be sharp and self-reliant when it comes to the basics. Here's a list to help you evaluate and hone your own skills - let us know in the comments if we've overlooked any skills that you've found indispensable!
1. Email - Knowing how to check your email, and how to write an effective email are two entirely different topics - but both are useful to know! Your email provider should have a "How To" on checking your email through webmail and setting up an email client on almost any platform, but if it's over your head, consider using a flexible, free service like Gmail, and forwarding your old email to your new one. Although almost any email address can be configured so that it's accessible over the web via browser or smartphone, Gmail apps make it easy for even the non-technically inclined to access their email anywhere.
On the writing effective emails front, check out mindtools.com's article on Writing Effective Emails.
2. Networks and Wi-Fi - Being unable to connect to the internet can derail a remote worker's entire day. Being able to troubleshoot basic network and wi-fi problems is a must. Also, consider a backup plan, if a tree falls on the telecom lines outside your house, where is the closest wi-fi hot spot?
C-Net has a good primer video on basic wi-fi troubleshooting, which is worth a view if your productivity (and your paycheck) is dependent upon a wireless connection.
3. "Instant" Communication, Skype, IM, etc. - Availability via IM can be either a blessing or a curse for a remote worker. Consider separating your business and personal life with separate logins for IM services so that you can tune out the chatter from friends, harness this tool for productivity, and gain a sense of "being there" with your colleagues even if you're far away.
4. Tele- and Web conferencing - Be sure to familiarize yourself with your client's preferred method of meeting. You can't blame it on traffic when you're late to a virtual meeting, and depending on your field, citing technical difficulties might make you look incompetent.
5. Collaborative Tools - Whether its as simple as Google Docs, or as involved as project management tools like BaseCamp, it's important that you can effectively use the tools that you have at your disposal.
For more a quick primer on Google Apps, check out Google's very own Google Apps Training Tutorial, and for some quick tips on how to use Basecamp more effectively, see Flatsourcing's "We <3 Basecamp. How we use it effectively."
6. Document creation and sharing - Being able to generate clear and concise documents, create the necessary delivery formats (ie, .doc, .pdf, .jpg), and share them via email attachment, web, ftp, or the collaborative tools mentioned above is an essential skill for any remote worker. A great free tool for creating PDF files is CutePDF, it's free and, once installed, is as simple as clicking "print".
7. Digital organization - Since the majority of remote work is digital, your computer desktop and local file structures are just as important as the desktop and filing cabinet you would keep at the office. It's easy - create new folders by right clicking on the desktop, select "New", select Folder, name it, put files and other folders in side of it according to the organizational structure that makes sense to you.
8. Screencasts/Screenshots - Sometimes its easier to just show someone what your talking about rather than trying to explain it. Being able to take a screenshot, circle part of the image and write notes can be a helpful way to illustrate a point. For explanations of more in-depth procedures, screencasts can be invaluable.
For more info, see About.com's How To Capture a Screen Shot of your Desktop or the Active Window in Windows.
For getting started quickly and easily with screencasts, check out NorthStarNerd.org's Tutorial on Camstudio.
9. Maintenance - Keeping a good eye on the health of your computer can prevent disastrous delays. Anti-virus and anti-malware are a great start, but your hardware's health is important too. Don't ignore noisy fans and cranky sounding hard drives! Most hardware failures give warning signs, don't ignore them.
For more info on computer maintenance see, Optimizing Computer Performance for Online Work Success, featured previous on the oDesk blog. For more advanced users, consider a hardware monitoring tool like SpeedFan, which can help you monitor CPU temperature, and overall hard drive health.
10. Security - Keep your sensitive data private. Run a good firewall, and keep your OS and browser up to date with security updates. For more security tips see, Securing Your Home Network, featured previous on the oDesk blog.