The Security Mentor

I've written about this before, but just ran into some really detailed instructions that explain what buttons to push and so on. http://www.us-cert.gov/reading_room/before_you_plug_in.html gives accurate advice and I think it's readable by normal people.

The Computer Emergency Response Team offers some other bits of advice for non-technical users. They're not all equally good. I like their advice about how to avoid phishing, their password advice is not bad, their "Understanding Firewalls" article packs good information into a quick read, but I'm not sure what else I'd recommend.