The speed of light (relative to the observer) varies with the speed of the observer. This is an antirelativistic statement which, somewhat paradoxically, is commonplace in the scientific literature. Scientists often forget to worship special relativity and produce texts like this one:

http://physics.bu.edu/~redner/211-sp...9_doppler.html
Professor Sidney Redner: "The Doppler effect is the shift in frequency of a wave that occurs when the wave source, or the detector of the wave, is moving. Applications of the Doppler effect range from medical tests using ultrasound to radar detectors and astronomy (with electromagnetic waves). (...) We will focus on sound waves in describing the Doppler effect, but it works for other waves too. (...) Let's say you, the observer, now move toward the source with velocity vO. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: v'=v+vO.. The frequency of the waves you detect is higher, and is given by: f'=v'/(lambda)=(v+vO)/(lambda)."

See more he

http://fqxi.org/community/forum/topic/1398
Shift in Frequency Implies Shift in Speed of Light

Pentcho Valev