Hi and welcome to Just Answer!
If your children are working - thay may need to file form 1040EZ - http://www.irs.gov/pub/irs-pdf/f1040ez.pdfHowever if they are required to file and if you may claim them as dependents - depends on their age, total income, and if they are still attending school.I will help you to determine requirements and will help to estimate their tax liability.
They have moved away and one is starting university. Neither lives with me anymore. I have no plan to put them on my 2011 return.
ages 22 and 19
total income is very low. maybe $60 per month
If your child is below 24 and is temporaty moved out because of attending school full time - he/she is still your dependent unless provides more than half of his/her own support.With $600 per month income - I doubt it woudl be more than half of support.
With total income from wages $600*12=$7200 - and being your dependent - estimated tax liability is $140.
22 year old has not enrolled in school and currently has no plan to do this. They both live together to share rent and other expenses
That is $140 per month for each of them.
Whoops. I mean $140 tax liability per year for each of them.
I thought that their income would put them down low enough where they would owe no taxes, but still have to file 1040EZ
22 year old who is not enrolled in school - may be your dependent only if his income is less than $3800(in 2011).If your 22 year old has $7200 taxable income - there will not be any tax liability and he is not required to file - but might want to file if any taxes were withheld and he wants to claim a refund. Yes - with income only from wages - he woudl use teh simple form 1040EZ that I references above.
I also wanted to be sure that the fact that they are green card holders doesn't change their tax filing obligations.
That is correct - green card holders are taxed the same way as US citizens.
Thanks. That is all very helpful.