Some question regarding MNP,

I am using Hotlink Maxis now, say now I opt for MNP then the iPhone 4 launch on the 24th. If I understand it correctly I cannot get the iPhone on-spot. I will need to come back another time after my number ported-in then only I can collect the iPhone.

If like that, anyone know roughly how long MNP process takes? If too long I think I better stick to maxis.