http://boyfriendgirlfriend.co.uk/audio.htmclick "infatuation dot com"... wait until 0:44 into the song.
That's a vocal effect I've never heard. sounds kinda like when you've got some phlegm stuck in the back of your throat and yu happen to be crying at the same time; not that that's ever actually happened but i assume that's kinda what it'd sound like.
How do you think it's done??