I looked into IDN issues extensively back then. They've been turned off by default... the original advisory was posted by the Schmoo group if I'm not mistaken. http://www.shmoo.com/idn/
I think this would only affect users who had it turned on (of which I know zero personally). It's just a con, and a bad one at that since you'd try to type it in and it wouldn't work. ;)
- RSnake
Gotta love it.
http://ha.ckers.org