Interestingly, I can't find that question. Of course my browser is acting up at the moment and cutting blog posts with a lot of comments. So, I decided to check google and see if it had anything to say about a cytochrome-c test for evolution. First off, I am suspicious of the 10^93 number. Oh, I am sure that Hubert Yockey has computed what he believes to be a real probability. But then, I believe the creationists are sincere when they trot out their "probabilities" too.
The big problem that I have with the claimed tests in general is that they are of a "confirm or inconclusive" form. If the data they take as confirmation were not there, it would not be disconfirmation. The same appears (to me) to apply to this test. If cytochrome-c were not found or were vastly different between chimpanzees and us, I don't see how that would constitute negative data. I believe large-scale evolution is plausible (though I don't think testable) and I don't see how that would have changed if that outcome had been different.
Something is a little more problematic for this particular test. Talkorigins reports that the cytochrome-c sequences in chimpanzees and humans are identical. Now, for the given probability to be meaningful, there can't be any selective pressures on those sequences. If there are selective pressures, then small-scale evolution (which is really a direct observation) will tend to lock them in and so the chances would not be so long. But if there aren't any such selective pressures, the sequences should have become different through mutation. We are talking millions of years and an imperfect replication process.
This test looks like an anomoly even if large-scale evolution is true. I don't see it being taken seriously unless people are blind to problems in the testing. Under the large-scale evolution hypothesis, human-chimpanzee similarities in cytochrome-c should indeed be greater than human-yeast similarities. But an identical form should mean either that there was not a branching off point millions of years ago, or that a selective pressure favors that particular form (in which case, the stated probability is not valid.)