If they are executed for their organs I would have a problem, otherwise I think it is a good thing.
I think it would be a nice gesture for those on death row to say sure you can use my organs. BUT, I am not sure if it is a good idea to just harvest them without a relative's consent, or the prisoner's permission prior to death. If they are selling them, then they should give part of the money to the executed prisoner's family. It is a bit creepy. But at least the organs are not going to waste.