Here, Jeff Head has a nice compendium of U.S. Sudden Jihad Syndrome events.
http://www.jeffhead.com/sjs/index.htm
Regarding how long, here’s a NY Times item from late 2006 recognizing it as a new buzzword/buzz phrase. Which means it had been around for a bit before that.
http://www.freerepublic.com/focus/f-news/1758178/posts
Looking at some other posts here, 2006 does seem to be the start of reasonably widespread use of the term.