PhysOrg reports that a vulnerability in the DNS addressing scheme could allow hackers to reroute you to a phishing web site, no matter what address you type into your address bar. It could have a potentially crippling effect on the Internet. Luckily the vulnerability was discovered months ago by Dan Kaminsky at IOActive, and several industry leaders, inlucing Microsoft, Sun and Cisco, have been working to repair it. The fix was released today, but your DNS may still be vulnerable. You can check at doxpara.com.
Edit: ComputerWorld has more extensive information on the DNS cache poisoning problem.