Discover magazine had an article on ultra-high energy cosmic rays
in the September 2003 issue that is currently available on the HiRes
cosmic ray detector's web site:

H i R e s / High Resolution Fly's Eye.
Sept. 2003 Discover Article.
HiRes's Pierre Sokolsky quoted in Discover© (Vol. 24, No. 9 September
2003) article, "They Came From Outer Space: Does The Very Existence Of
Cosmic Rays Defy The Laws Of Physics?" (pg.44-47).
"Some physicists argue that at high energies, even the speed of light
may vary—posing a serious problem for Einstein's special theory of
relativity, which states that the speed of light is constant, always
and everywhere. With a speed-of-light loophole, ultrahigh-energy
cosmic rays could travel greater distances than the experts suppose
without getting bonked by background radiation. Evidence of their
sojourns should turn up in data from the next generation of cosmic-ray
detectors. If the source of those most powerful of particles turns out
to be far enough away, Einstein himself could get a makeover."
http://hires.physics.utah.edu/

See also this:

Interpreting the Cosmic Rays.
New York Times, December 31, 2002
"Was Einstein wrong? The answer may come from the Pierre Auger
Observatory under construction in Argentina."
http://courses.washington.edu/phys55x/Interpreting%20the%20Cosmic%20Rays.htm

Bob Clark