Alas, it’s not a joke.

WebMD’s lupus awareness campaign
Lupus Foundation of America (US specific, but useful to anyone who can read English)

The Hospital for Special Surgery’s Rheumatology Division (particularly good for looking for infomation about related conditions or mixed connective tissue disease)

The National Institute of Arthritis and Musculoskeletal Diseases at the National Institutes of Health (and a link to the White House’s National Bone and Joint Decade Proclamation)

The National Library of Medicine’s lupus page on MedlinePlus

The Lupus UK site is also very good and has links to other European organizations.

In keeping with our canine-related them of late, here’s a site about dogs with lupus.

Here’s eMedicine’s lupus page and here’s the one maintained by the Mayo Clinic

And last, but not least, in keeping with the April Fool’s theme, here’s the Centers for Disease Control’s Health related hoaxes page. The Urban Legends Reference Pages has, of course, lots of hoax info as well.