According to this article in TechWeb, SSL is to be axed in IE 7, replaced by TLS, a stronger version of SSL.

Also, 

“IE 7 will also block access to Web sites that offer up a problematical digital certificate. If a certificate’s been issued to a host name other than the URL’s actual hostname, or the certificate was issued by an untrusted root domain, IE 7 will put up a message that explains the problem. If the user chooses to proceed, IE 7 will tint the address bar red as an additional warning.

Additionally, said IE program manager Eric Lawrence in the group’s official blog, the Windows Vista version of IE 7 — the browser will come in two editions, one for Vista, the other for the current Windows XP SP2 operating system — will include new encryption algorithms, such as AES (Advanced Encryption Standard).”

Alex Eckelberry