They do a lot of different stuff, so I'm sure they all make different money.
Stuart Scott works as a sideline reporter as appears in many other ESPN productions, Mike Greenberg is part of Mike and Mike in the morning (i think). I imagine they are all signed to different contracts with ESPN, and there isnt a single contract for just being a sportscenter anchor.
So I havent answered your question, but heres a clue.
I saw Stuart Scott boarding a Southwest Airlines flight in Durham, NC. So I'm guessing he makes 100-250k a year. Rich, but still flying Southwest.
(this isnt a knock on Southwest, I fly them all the time)