Whether he's still governor or not, Spitzer should fight this. These are minor crimes that people get slapped on the wrist for all the time--felonies or not.
The main thing is that there are so many bad things happening to good people around the country that are being ignored while the FBI is going afte victimless crimes instead of, say, the deliberate destruction of the Gulf coast through negligence, willful neglect, deliberate theft and deception or the outing of a covert CIA operative or rampant election fraud.
And they're going after prostitution? It's ludicrous.