The speed of receipt is indeed affected and there is indeed a change of frequency, resulting in a "red shift," which gives us information about the speed at which something is receding from us. It's frequently described as a Doppler effect, similar to what happens when a train whistle passes us. That's OK as far as it goes, but be careful with the analogy -- Doppler effects on sound on earth are mediated by the atmosphere, making significant differences from what happens with things radiating in space. You don't say so, but it sounds like your question springs from a conflict between what you know to be observed effects -- the red shift -- and what you may have heard about the speed of light being invariant, as is required by the Special Theory of Relativity (and modified by the General Theory). (Actually the spped of light being invariant was required by math that came into existence before Einstein; what he did was resolve the conflicts between that and the rest of what we knew about the universe by realizing that time and space must not be invariant.) If you're confused by that stuff, welcome to the club. The good news is that there are a lot of good books out there aimed at sorting out relativity for a general, non-mathematical audience. Einstein himself wrote one in 1916, and he's a wonderfully clear, understandable writer (what little math couldn't be left out you can skip if need be -- the book is about the ideas). And there are a lot of others, e.g., Epstein, Lewis C., "Relativity Visualized" (Insight Press, 1988). "Pictures to aid the mind's eye in understanding difficult concepts." Epstein is as engaging a writer about physics as you're going to find. He is dedicated to creating pictures that will communicate underlying ideas (and is disdainful of people who think they understand physics because they understand the math, without ever having really thought about the ideas). He is also the author of "Thinking Physics" (Insight Press 2002), which is a wonderful compendium of one- and two-page problems about everyday phenomena designed to lead the reader inexorably to, well, thinking physics. (I've recommended it elsewhere on this site.) Schwinger, Julian, "Einstein's Legacy" (Freeman, 1987). Schwinger is a Nobel laureate in physics, and I believe this is one in a series of Scientific American books about the sciences. Still directed at a general audience, but maybe not quite as general -- a little more knowledge assumed, a little more detailed information laid out. What I've seen of this series are all very useful.

The Doppler shift observed by astronomer Edwin Hubble is a phantom. Light simply slows down over vast distances. Sorry, no bang. The universe is simply swirling at random. When enough matter collects into a lump, the gravitational forces are so strong that the atoms grind together and decompose back into photon particles, or starlight. Then the photons re-collect back into dark matter starting the process over again. This is the formula - E = MC 2 for decomp, and MC 2 = E for re-comp. All atoms are made of light. You can repeat my famous experiment if you would like to prove this...Alfred Herman Schrader

Ever notice how when a train or a vehicle with a siren is higher pitched when it's heading towards you, and lower pitched when it's going away? The same thing applies to light.