Let me be the devils advocate here. The accusations against Zardari are just that accusations. He has never been found guilty of any crime ever so why should he resign? Let the cases be proven in courts, and if he is found guilty of crime let him face impeachment, but until such time he should not resign.
well strictly speaking, all the cases are not just accused or on going. swiss cases, they have been convicted by swiss courts already.
on the issues, its nice little game , you get the special treatment before you get elected without that one wouldnt have been a elected anyway. but once you become president, you are immunised :) people with no moral will not be deterred. I dont think Zardari will be resigning. would anybody? after resigning he will loose all immunity and may be straight to jail again! he wouldnt be signing his own warrants!