I moved to a new state on 1/1/08. Must I still pay 2007 state income tax to my old state?

Yes! You pay 2007 taxes to the state you lived in. If you don't, it will take a couple of years to catch up to you and then they will file a tax lien and you will not only have the penalties, but also the interest charged for all that time. Also, you need to make sure you prove to them that you moved in 08 so that they won't come after you for those taxes as well.

Take a look at your 2007 W-2(s). More likely than not you have already been paying state taxes to your former state of residence all throughout the year. Filing a return is required by law because you've enjoyed the benefits of living in the state and may even net you a refund.

Interest on any unpaid taxes will average about 8% and penalties will depend on which state you were living in and how much (if any) unpaid taxes you owe the state.

Good luck.

If your earnings in the "old state" were above that states filing requirements and you had earnings in that state you should file a return in that state. The penalty for not filing if you are required to do so would depend on the level of income, tax due if any and the amount of time until you do file if so required.

If you did not owe any tax or very little they are not likely to do anything. If you owe thousands they will track you down in your new state and garnish or levy everything you have.

Well, yes, you lived there in 2007, didn't you?

Penalties vary by state. Just pay it - they WILL come after you otherwise if you owe more than a few dollars. And if it's just a few dollars, why not just get it out of the way?