True.

Jan 1st I deactivated my account, which did _absolutely nothing_.

After googling, I found a hidden "Delete Account" which did the job.

There's a good explanation by Patricia Burchat in a TED talk: http://www.ted.com/index.php/talks/patricia_burchat_leads_a_search_for_dark_energy.html

If impatient, jump to 4:20 for how do they use lensing.

Connexions (http://cnx.org) is a rapidly growing source of complete courses (including text), all under a creative commons license. Subjects range from electrical engineering, to modern music appreciation. There is a lot of material already. Please check it.