I came to U.S.A on 5th Aug 2006 for the first time .My status for 2006 was non resident alien since I haven't completed 183 days.I understand my status will be resident alien in july 2007.At that time can i file an amended return for 2006 as a resident alien ? Since this time i filed the return as a non resident alien, i could not claim any standard deduction.In amended returns i would like to apply jointly and claim standard deduction.Please let me know if i can do so.

You CANNOT file as a resident alien in 2006 UNLESS you are married and you and your spouse BOTH choose to be treated as resident aliens for all of 2006.