1) 1) You can file singly if you like - hence, she files MFS and you don't file.
1) 2) You convert from UK£ to US$ on a calendar year basis. I hope you saved the payslips. The P60 is useless as it's April - April.
2) This requires an extensive determination as to your wife's domicile and residency status. If she is Resident But Not Ordinarily Resident and non-UK-dom, then a portion of the US wages may be tax-free. If she is Ordinarily Resident, it would be taxed here.
3) Once you have your greencard, it has to be activated for you to be subject to US tax. It is activated upon your first entry to the US after obtaining the card. For example, if you get the card Dec 2006 but do not enter the US until 2007, you are resident starting 2007, not 2006. If you enter the US for 10 or more days prior to activation in any calendar year, then the date may be your first entry date in the US that year. It's a bit tricky, you should get confirmation once the dates are clearer.
IRS Circular 230 Disclosure: To ensure compliance with requirements imposed by the U.S. Internal Revenue Service, we inform you that any tax advice contained in this communication (including any attachments) was not intended or written to be used, and cannot be used, by any taxpayer for the purpose of (1) avoiding tax-related penalties under the U.S. Internal Revenue Code or (2) promoting, marketing or recommending to another party any tax-related matters addressed herein.
