As suggested by few of my folks who have cleared the test, the ideal time should be of 1 month preparation with 2-3 dedicated hours a day,if you know the basics.
But my suggestion will be to take 2 months of time, write online exams as many you can, solve as many papers you can.
I am also planning to take the test in May end.
[ March 27, 2008: Message edited by: Milton Singh ]