How do I file taxes this year?

Your filing status should reflect your status on the last day of the year. You should file single,

From IRS publication 17. www.irs.gov

Divorced persons. If you are divorced under a final decree by the last day of the year, you are considered unmarried for the whole year.

If your divorce decree, gives your ex custody, then you can not file as “head of household”.
If you have minimal income, let him take the deductions, they are worth more to him than you

@srmorgan, Thank you for the publication number! I have searched it a couple of times but I must not have put in the best terms. Lurve!

http://www.irs.gov/publications/p17/ch02.html

DO NOT FILE SINGLE unless he has custody of all the kids

If You have any of the kids, that makes you head of household.

If you agreed that Dad gets the deduction, only the person who has physical custody can get the child tax credit.

Although Pub 17 states a person who is unmarried on the last day of the year is single, it also say that a single person with children can file as HOH.

If you have the patience, you can call the IRS helpline and ask them.