I am a permanent resident in USA for last 5 years and have sumitted Federal and State tax returns on regular basis jointly with my spouse. We even got our tax refunds as and when applicable.

We now realize that we probably should have some alterations, and may like to resubmit some of those returns. Our questions are:

1. For how many years we can resubmit.
2. Can we get more refunds, if applicable.
3. Are there penalties, and at what rate, if there are tax dues as per new submission?

Thanks in advance for help.

You are NOT re-submitting tax returns; you are amending them (using Form 1040X).

1) You can amend back as far as you want.

2) If the amendment results in a refund, you will get the refund ONLY for 2004, 2005 and 2006. It is too late to get any additional refund for 2003 or earlier UNLESS you filed and paid taxes late.

3) If you are getting an additional refund, there are NO penalties or interest. If you OWE taxes as a result of the amendment, you MUST pay interest (required by law), but you can ask that the IRS waive any late payment penalties, which the IRS normally will waive if you are coming forward voluntarily.

If you need professional tax help, contact me at the email addess below.