As a new immigrant, for the first time if I land in USA on last day of the year i.e. on 31st December 2009 or alternatively on 1st January of 2010, then what will be my tax filing requirement? i.e. in the first case will I be considered resident of USA for tax purposes for 1 day in year 2009 even though my physical presence is not for a full 24 hours on that day?
In the second case when arriving on 1st January 2010, will be considered DUAL status with 1 day ( 1st January 2010) as Non-resident and balance 364days as Resident or I can file for full year of 2010 as Resident.
Can you kindly clarify?

You do not file 2009 tax return. You will file 2010 tax return as resident.