If you haven't purchased a "digital" television ("SDTV" or "HDTV") yet and you get your local channels from "rabbit ears" or roof-top antenna, then you NEED to worry about June 12th, 2009.
For those of you with cable or satellite hooked to your old ANALOG television, you DON'T need to worry (it's your local satellite/cable provider's LEGAL responsibility to keep broadcasts coming to your house after 6/12/09).
You can see below the 3 flavors of "digital" televisions ("SDTV", "HDTV" and "Full HD"). Obviously purchasing an "HDTV" would cost more than an "SDTV" (and "Full HD" sets cost even more than "HDTV" sets).
If you've already purchased a "digital" TV you can get FREE Hi-Def (or Standard-Def) channels with your roof-top antenna or "rabbit ears". Switching from analog to digital will more than DOUBLE the number of channels you receive over the air with an antenna.
If you've already purchased a "digital" TV, just because you have "digital" satellite or "digital" cable doesn't mean you're watching High Definition programming. You need an HD cable/satellite box and an HD programming package from your local provider.
Most importantly, the ONLY thing that changes for ANALOG televisions on June 12th, 2009 is that they no longer receive local broadcast channels from an ANTENNA. Everything else you own will still work like it always has on those TVs (essentially turning all ANALOG televisions into "MONITORS").
Here are some links that might answer a few more of your questions:
Explaination of PICTURE QUALITY in televisions
Click here of your (2) $40 Government coupons towards (2) HI-DEF COVERTER BOXES
FCC's DTV Reception Maps (find the number of stations and signal strength in your town)
Click here to see an ENTRY LEVEL "Standard-Def" television @ "Bestbuy.com"
Click here to see an ENTRY LEVEL "High-Def" television @ "Bestbuy.com"
Click here to see an ENTRY LEVEL "1080P-FullHD" television @ "Bestbuy.com"
Click here to see an ENTRY LEVEL "Set-Top Decoder Box" @ "BestBuy.com"
For great deals on the latest HDTV technology and award-winning customer service, visit HDTV Depot