Hi,

I was on an H1b since 01/2005 and became a GC holder on 1/23/09.
My wife was on an F1 since 09/2006 and became a GC holder on 3/31/09.

I know that my tax status has not changed, but I have a few questions regarding my wife:
1) is my wife now a dual-status alien for 2009? If yes, does she have to file both the 1040 and 1040NR forms?
3) can we file jointly?
4) is she required to pay social security tax for her wages when she held an F1 in 2009?

Thanks.

3. Yes you should file joint return.
4. No

You should probably make this election: U.S. Citizens and Resident Aliens Abroad - Nonresident Alien Spouse (http://www.irs.gov/businesses/small/international/article/0,,id=96734,00.html) & file a joint return (Form 1040).