Yes, if you work outside of the US occasionally. You may treat the proportionate income you earn during your work days in foreign countries as foreign-sourced income for purposes of the foreign tax credit.

Although there is no definition of the type of income to include in gross income on the foreign tax credit form in the Internal Revenue Code (IRC) sections 901 through 905 dealing with the foreign tax credit, the 2008 instructions for Form 1116, Foreign Tax Credit, on page 13, column 1, under the heading, Lines 1a and 1b — Foreign Gross Income, say, “You must include income even if it is not taxable by that foreign country. Identify the type of income on the dotted line next to line 1a. Do not include any earned income excluded on Form 2555.” It refers to earned income, and, since you have not excluded that earned income on Form 2555, it needs to be included on the gross income line of Form 1116.

Instead, the income-sourcing rules are found in IRC sections 861 through 865. They support reporting your foreign earned income on Form 1116. IRC section 862(a)(3) states that gross income from “compensation for labor or personal services performed without the United States” is foreign-sourced income. Treasury Regulation section 1.861-4(a)(1) says that the residence of the recipient, the place of contracting, and the time and place of payment are irrelevant. This regulation deals with US-sourced earned income, though. There is no similar regulation with respect to foreign-sourced earned income. But in the absence of specific guidance or anything to the contrary, I believe you may safely rely on IRC section 862(a)(3) to report your foreign work days yielding foreign-sourced earned income on the foreign tax credit form and to take advantage of your unused foreign tax credit carryovers.

Note: The instructions for calculating the foreign earned income exclusion (Form 2555 and IRS Publication 54) state that you cannot include foreign earned income in the calculation unless your tax home is outside of the US. There is no reference that the foreign-tax-home restriction applies to the foreign tax credit. This restricted definition of foreign earned income is only for the purpose of calculating the foreign earned income exclusion. See Internal Revenue Code section 911 (the section that allows the foreign earned income exclusion), subsection (a)(1), which states, “Definition. For purposes of this section — (A) In general. The term “foreign earned income” …” It goes on to cite the foreign tax home restriction referenced in Publication 54. Therefore I conclude the foreign tax home restriction does not proscribe including foreign-sourced gross earned income on Form 1116 for computing the foreign tax credit.