Does anyone's cable TV provider offer HDTV?

Does anyone know if cable TV providers will soon offer boxes capable of HDTV? Do youy already have such a service in your area? (My service just switched from AT&T Broadband to Comcast, but I still just have the basic CATV box). Many prime time network shows and sporting events will be broadcast in HDTV this year. I do not want to switch to satellite if cable TV will soon catch up because my internet access comes in over the same cable and it is very convenient to use a simple splitter, and then be billed for both services by the same company.