With regards to the USA Digital TV Conversion, the mandatory switch was delayed from Feb 17 to June 12.
However, some stations voluntarily switched on Feb 17, such as:
Kentucky: LEX 18
Louisiana: KALB, WNTZ
Wisconsin: WSAW, WJFW, WAOW/WYOW.
Missouri: KHQA-TV, WGEM-TV
North Dakota: Most stations.
South Dakota: Public Broadcasting
Vermont: WCAX-TV, WFFF-TV, WNNE-TV, WPTZ-TV, WVNY, Mountain Lake PBS and Vermont Public Television
A full list is available at the FCC site.
With a typical switch over, some stations were off-air for 30 minutes while transitioning, where others were simulcasting digital and analog, and simply pulled the plug on the analog.
So why did they switch early? Simply put, it can cost millions to maintain simulcasting the additional months.
Why switch at all? The new digital TV signals are 4 times higher quality than the old signals.
The bad news: If you previously received a station that was a bit snowy, but tolerable, it is possible the new digital TV signal will drop entire frames.
With the Internet and Spreety, why do we care? The frequency spectrum freed up by removing the analog signals is partially slated for high speed wireless Internet.
Since the change to June 12 was announced rather late in the game, several TV episodes had already been created in High Definition. An example is The Simpsons, which overtly celebrated the HDTV transition, without the transition. The HDTV version is available on the FOX web site.
To find the rest of the tv shows online, go to Spreety.com.