Facebook today announced through their fan page they have discontinued the “Lite” version of the site:
Thanks to everyone who tried out Facebook Lite. We're no longer supporting it, but learned a lot from the test of a slimmed-down site. If you used Lite, you'll now be taken to the main Facebook.com site.
Introduced last Fall 2009, Facebook Lite was intended for users with slower connections and computers. The minimized version stripped down the interface to its bare essentials in order to speed up loading and fit within smaller display resolutions.
It is not yet clear why they chose to discontinue the service, though indications point to extraneous costs in maintaining two versions of the site (in addition to their mobile site).