Yes, the government-subsidized tuners will accept coax. However, not all of them have RCA (red-white-yellow) analog output.
Take a look at this for more information:
http://www.neurostechnology.com/digital-ota-conversionI assume you are watching TV from an antenna? If so, you may want to get a digital converter box that has RCA (red-white-yellow) outputs, because, come February 17, 2009, you will not be able to watch *any* TV without a digital tuner.