Please see the following web pages for useful reference articles about digital TV standards and compatibility:
Overview of Digital Terrestrial TV -
http://www.answers.com/main/ntquery?method=4&dsid=2222&dekey=Digital+terrestrial+television&curtab=2222_1
List of Digital TV Broadcast Deployments by Country -
http://www.answers.com/main/ntquery?method=4&dsid=2222&dekey=List+of+digital+television+deployments+by+country&curtab=2222_1
Overview of Digital TV Technology -
http://www.answers.com/main/ntquery?s=digital+television&gwp=13
Digital TV Terminology -
http://www.answers.com/topic/list-of-digital-television-terms
Digital TV in Australia -
http://www.answers.com/topic/high-definition-television-in-australia
Freeview Channels in the UK -
http://www.answers.com/main/ntquery?s=Freeview&gwp=13