http://www.irs.gov/publications/p519/ch06.html
They use a UK citizen as an example in the bottom of the link. IRS shows how
to
split the income, together with filled 1040NR and 1040 forms. 1040NR is
just a "statement".
My personal opinion: since you are "resident" on the last day of the tax
year, you estimate the tax you owe using 1040.
