Facebook recently enabled secure browsing, via https, but the feature has gone relatively unpublicized in this country. Note that, if you do not turn this on, your account can be hacked relatively easily, via packet sniffers, especially when using non-secure connections (such as public libraries, coffee shops, restaurants).
Switching to secure browsing is easy and is a one-time thing.
1) Hunt down all your bookmarks, in your browser, and change Facebook to be https://www.facebook.com/ .
;; To change a bookmark, in most browsers, simply hover over it, right-click, and go to 'Properties'.
2) When logged into Facebook, go to Account|Account Settings|Account Aecurity. Enable 'Browse Facebook on a secure connection (https) whenever possible' and 'When a new computer or mobile device logs into this account' (Send me an email).
3) To be safe, change your Facebook password after performing the above steps. Sure, you might have to change your phone's entry, your various PC's entries, your applicable home media servers' entries…but it's worth it.
– Dan Reams, February, 2011
Update: Check out http://www.simplehelp.net/2011/02/12/how-to-fix-the-secure-https-connection-flaw-in-facebook-after-visiting-an-unsecure-http-page/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+simplehelp+%28Simplehelp%29 for a note about how this setting can be reversed, if one visits a non-secure site, and how one then later has to re-enable this option. -d.r., 2011-02-13