Offical Gov DTV website
First off, Digital TV (DTV) isn't HDTV, it just refers to a required digital signal versus analog. Not everything must be broadcast in HD, it just must be broadcast as a ditigal signal. SDTV (standard Def TV) will still exist. As was said, if you have cable or sat tv then this won't really effect you, as it's up to sat and cable broadcasters to decide what they want to do with the signals over their lines and networks.
Over the air will be effected, and in order to view TV signals broadcast over the air, you will need a ditigal TV (SDTV, EDTV, or HDTV) or a ditigal to analog convertor box. The reason for this is the government wants to return the valuable analog spectrum for use by emergancy crews, and some say to "auction it off" to help pay of defict.
this site gives some in depth info on it
Benton Foundation, More DTV Info
Here's the reason for it given on the gov site...
Why are we switching to DTV?
DTV is a more flexible and efficient technology than the current analog system. For example, rather than being limited to providing one “analog” programming channel, a broadcaster will be able to provide a super sharp “high definition” (HDTV) program or multiple “standard definition” DTV programs simultaneously. Providing several program streams on one broadcast channel is called “multicasting.” The number of programs a station can send on one digital channel depends on the level of picture detail, also known as “resolution,” desired in each programming stream. DTV can provide interactive video and data services that are not possible with “analog” technology.
Converting to DTV will also free up parts of the scarce and valuable broadcast airwaves. Those portions of the airwaves can then be used for other important services, such as advanced wireless and public safety services (for example, police, fire departments, and rescue squads).
also from the Gov site...
Once broadcasters transition from analog to digital, will analog televisions will be obsolete?
No. Set-top boxes which convert digital signals to analog signals are available now and will continue to be available at lower prices to consumers as the transition progresses. However, to enjoy the full benefits of Digital TV, including superior sound and clarity, you must own a Digital TV set. An analog television, with the addition of a set-top box, will still allow viewers to enjoy all of the programming they have always enjoyed.
Here's some info-timeline on it from the Benton site...
2007
October 2007 -- September 2009 The NTIA is to make payments of up to $10 million to implement and administer a program through which eligible low-power television stations(6) may receive compensation toward the cost of the purchase of a digital-to-analog conversion devices that enable them to convert incoming digital TV signals of their corresponding full-power television stations to analog format for transmission on the low-power television stations' analog channels. Requests for such compensation must be made on or before February 17, 2009. Priority compensation is to be given to non-profit corporations and stations that serve rural areas of fewer than 10,000 viewers.
2008
January 1, 2008 -- March 31, 2009 US households may obtain $40 coupons towards purchase of digital-to-analog converter boxes by making a request. All coupons expire 3 months after issuance. The NTIA is to ensure that each requesting household receives, via the United States Postal Service, no more than two coupons.
January 28, 2008 The FCC must conduct the auction of the licenses for recovered analog spectrum, commencing the bidding no later than this date, and is to deposit the proceeds of the auction in the US Treasury no later than June 30, 2008.
June 30, 2008 By this date, the FCC is to have deposited in the Treasury proceeds from the auction of spectrum currently used for analog TV broadcasts.
October 2008 -– September 2009 The NTIA is to make payments of no more than $65 million to implement a program to reimburse rural low-power television stations for upgrading to digital TV technology. Such reimbursements shall be issued to eligible stations no earlier than October 1, 2010. Priority compensation will be given to non-profit corporations and stations that serve rural areas of fewer than 10,000 viewers.
2009
February 17, 2009 Analog TV broadcasts from full-power TV stations in the US ends. Low-power stations, including Class A stations, may continue broadcasting in analog format after this day, subject to future decisions by the FCC on how to complete the digital television transition for such stations.
February 18, 2009 By this date the FCC must require that all TV broadcasting occur only on channels between channels 2 and 36, inclusive, or 38 and 51, inclusive (between frequencies 54 and 698 megahertz, inclusive). If low-power stations want to be compensated for digital-to-analog conversion devices, they must make request by end of day.
September 30, 2009 On the last day of Fiscal Year 2009, the Secretary of the Treasury will transfer $7.363 billion from the Digital Television Transition and Public Safety Fund to the general fund of the Treasury.
Basically, this isn't a push for HD, and just because this happens doesn't mean the signals will all be HD. It just means that over the air signals must be digital signals. They'll still sell TV's same as today (SDTV, EDTV, HDTV).
Directly from the gov site...
Is HDTV the same thing as DTV?
No. HDTV is the highest quality of DTV, but it is only one of many formats. In addition to HDTV, the most common formats are Standard Definition Television (SDTV) and Enhanced Definition Television (EDTV).
SDTV is the baseline display and resolution for both analog and digital. Transmission of SDTV may be in either the traditional (4:3) or wide-screen (16:9) format. EDTV is a step up from Analog Television. EDTV comes in widescreen (16:9) or traditional (4:3) format and provides better picture quality than SDTV, but not as high as HDTV.
Anyways, sorry to bring this up from a few pages back, but I noticed a few ppl were talking about it, and I thought maybe this would help clear things up in that department. I hope it helped.
Washington Post Article on it