I came to USA with F-1 visa on 8/15/2004 and graduated for my master degree in May 2008. Then I worked in my OPT for about a year and transferred my visa to H-1B on 10/1/2009. It seems like I am dual status aliens in 2009, and not meet the substance presence test--only 139days in 2009. If I file as dual status resident, I only get around $100 refund so I am thinking of file an extension and use the standard deduction when I file 1040 for 2009 so I could get more refund. Can anyone tell me how could I file an extension? I didn't notice I have to pay the FICA SS & MC after 8/15/2009 so I didn't pay them until 10/1/2009. Right now I have 2 W-2--one is for the period 1/1/2009 to 9/31/2009 without FICA tax and one is for 10/1/2009 to 12/31/2009 with FICA tax. Should I contact HR to get revised W-2 or should I send IRS the FICA tax that I missed to pay?
I know it sounds confusing but I am really appreciate for all your help and suggestions!
Thanks

You will file resident tax return for 2009. You are not dual status.

I have similar case- I worked as OPT from July 2008 through 2009. My employer applied for my H1b was approved on December 4, 2009. Do I also file a resident tax?

You CANNOT file as a resident in 2009 even if you are married, because you did not spend at leaast 31 days in H-1B status.

File as a non-resident alien.