Dump it!
It's official: The U.S. government's Computer Emergency Readiness Team (US-CERT) is warning Web surfers to stop using Microsoft's Internet Explorer (IE) browser.
"US-CERT is a non-profit partnership between the Department of Homeland Security (DHS) and the public and private sectors. It was established in September 2003 to improve computer security preparedness and response to cyber attacks in the United States."
...
"US-CERT researchers say the IE browser does not adequately validate the security context of a frame that has been redirected by a Web server. It opens the door for an attacker to exploit the flaw by executing script in different security domains."
So what are you waiting for? Get a real browser, like Mozilla, Firefox, or Opera...