Oberlin College physicist Daniel Styer has published a brief, but very useful, article in The American Journal of Physics showing that even under very conservative assumptions the change in entropy of the biosphere as the result of evolution is negligible compared to the entropy flux of the Earth that results from the Sun’s heating. Sadly, I know from personal experience that this sort of thing tends to leave creationists unimpressed. This is because their arguments use only the language, but not the substance, of thermodynamics. Their assertion that evolution violates the second law is not really an invitation to carry out entropy calculations. Rather, it is just another incarnation of ye olde argument from incredulity, in which they express the difficulty they have in believing that fully naturalistic processes can explain the growth in complexity in organisms over time.
I provide some details in my post. Enjoy!