is currently being implemented "... use Facebook HTTPS by going to Account Settings and then selecting "Account Security," third from the bottom. Then click under "Secure Browsing" — if it's there. Facebook says everyone should have this by the end of the day, but in the meantime you might be missing the relevant option toggle..."
if you use FireFox then try
http://www.eff.org/https-everywhere it forces HTTPS for all these websites
Google Search
Wikipedia
Twitter
Facebook
bit.ly
GMX
Wordpress.com blogs
The New York Times
The Washington Post
Paypal
EFF
Tor
Ixquick
this will slow down your connection, in return you get browsing privacy