I am trying to fill out a W4 form for a 3-week summer job, but am having some complications.

I am a US citizen from Pennsylvania, but I have lived in Spain since June 2008. I am married to a Spaniard who also lives and works in Spain. Should I file as married or single or married filing separately?

I do not know how many or which exemptions to claim on the W4 as I am technically married, but it doesn't seem that my husband's earnings should be taxed by the U.S. government. Additionally, the only U.S. income I will have for this tax year in the U.S. will be from this brief period of employment.

Additionally:
Where does my tax residence lie? (I still bank in PA and have come home to visit several times. I was given legal residence in Spain in February 2009.)

THANKS for your help!

You can file as married filing jointly or married filing separately.
If you file joint return, then both of you must declare your worldwide income for the year.
If you file a separate return, then you spouse in not required to file.

However, if you file MFS, you CAN claim his exemption if he is not filing and has no income that is subject to U.S. income taxes.

You would list his name and put "NRA" where his SSN would go.

This return would have to be mailed (no tax software will accept it for efiling without an ITIN or SSN for your husband), but it is worth it to get an additional $3,600 deduction on your return.

To answer your question about residence, your tax home is Spain.

If you satisfy the rules regarding physical presence, you may exclude all your income using form 2555 or 2555EZ.

There is no such thing as "technically" being married.