Scan Files for Viruses -- Before You Download Them
You just never know if the file you're about to download contains a virus. Sure, the anti-virus software on your PC (you do have some, right?) should catch any infections, but what if it doesn't? In an ideal world, virus scanning would occur before the download.
That's the idea behind VTzilla, a Firefox add-on that scans files for viruses before you download them. Once installed, it adds a Scan with VirusTotal option to Firefox's download dialog box (which appears when you click a file).
VTzilla also adds a scanning option to Firefox's context menu. Thus, you can right-click any suspicious-looking link and choose Scan with VirusTotal. That's great for ferreting out suspected phishing sites (like the LinkedIn ones I mentioned yesterday).
Either way, a scan leads to a new tab where VirusTotal's dozens of anti-virus engines kick in. When they're done, you'll know if it's safe to download the file (or visit the site).
I'd say VTzilla is a must-have for security-conscious Firefox users. It's free, easy to use, and potentially a lot more effective than the AV software residing on your PC.
Not a Firefox user? Check out my original coverage of VirusTotal, which still allows any user to e-mail or upload a suspicious file for scanning.