My wife went to Texas to see her dying mother. She says she has met someone
Else and isn't coming back. She has been gone since the first week in may, 2008.
I have taken care of our 3 children and a full time job since she has been gone.
Now, this week she came to Nebraska, not telling anyone she was coming. She
Took our children, took no clothes or anything and took them back to Texas. I want
My children back. What rights do I have?

You need to file right away for divorce and custody before this goes any further. Make sure you get temporary custody till the hearing. That way you have the right to get your children back by court order. You will be filing in your state as she hasn't lived long enough to have residency in any other state. Also make sure to get a bench warrant for her to appear.

Well as soon as she took off, you were suppose to go to court and file for a order of custody, So now you wlll have to hurry and get to court and file for divorce and custody of the children