Some time ago (a few years) I found free access to worldwide IFR enroute charts (Hi and Lo) on a US agency website. As far as I can remember it was one of these agencies you don't want to be messing with, specially nowadays (DoD, CIA, ...)
It was bookmarked on a computer I had to reformat
Never been able to find the site again. After 9/11 I may even guess that the access has been removed.
Cheers
