Can anyone help me out with the new digital TV stuff?

Ok here is the deal, my elderly parents do not have cable TV nor do they want it. We have heard that within the next year that a new digital program is going to take effect. If you don't have cable, you can't watch TV, (the screen will be real "snowy"). But we have also heard that there is a box that seniors can get free for their TV so that they can still watch TV and not have to get cable. Does anyone know about this and if seniors can get this box for free, who do I contact? We do live in Oklahoma. I don't know that much about this topic as you can tell, sorry.