Hi,

My wife and I have a visa J1. We will come back in Belgium for good on August 15, 2011. My wife was a teacher so she stopped to work on May. She has to pay tax. Can we fill the federal and state tax for her in July (before leaving US)?

Thank you,
Sebastien

You cannot file the tax return in July, you will have to wait for next year. The IRS starts accepting tax returns around the middle of January. But you should make sure that you have all your necessary forms before that (W2s, 1099 INTs etc).
You would be resident aliens for 2011. In that case, you would need to report worldwide income. However, you could apply an early termination date and file as dual status alien (1040 for the time you were in he US, 1040NR for the time after).
Have a look here:
http://www.irs.gov/businesses/small/international/article/0, id=96389,00.html
Also make sure, that all places sending you tax forms have your updated address, so the forms won't get lost.

http://www.irs.gov/taxtopics/tc157.html