6. Keep your OS and apps up to date. It seems that almost every week there's a new "security patch" for various parts of the Windows operating system or Office programs. And it's not just Microsoft. Apple has its own fair share of security updates, as do most utility and business software vendors. Most of the malicious viruses and worms that have plagued users recently spread through email, so be especially cautious about opening attachments.

Windows users should enable Automatic Updates or visit the Windows Update site to scan your system and identify patches you may be missing. Mac OS users should enable the automatic Software Update feature in System Preferences; and Linux/UNIX users can visit sites such as Bugtraq or subscribe to receive bulletins and alerts from the Department of Homeland Security's US-CERT.

7. Be aware of people around you. When you're at an ATM, you make sure noone can see you type your PIN. Be just as careful about typing in your name and password at a Starbucks. You pay big bucks for your T-Mobile access!

8. Use Web-based email when you're connecting at a public hotspot, instead of Outlook or Apple Mail. Most ISPs these days let you send and receive email via a Web interface as well as downloading it into your email program. These Web sites generally use secure sockets layer (SSL) or other security protocols, which protect your data while it's being transmitted.

9. Make sure file sharing is off! On home networks, file sharing is frequently used to copy files back and forth between computers. On a public network, this is the last thing you want to have on, for obvious reasons. If necessary, put a sticky note on the edge of your computer screen reminding you to turn it off before you close your laptop. Just don't write your passwords on the same sticky note...

10. Use passwords for personal data. Our final tip: use strong passwords for sensitive files and folders, as well as for access to your computer as a whole. This is especially important for mobile warriors whose laptops are attractive theft targets. Consider keeping your most important data on an encrypted USB keychain storage device, so even if you lose your portable, you won't lose your presentation or email folder.