Couple of things to remember if you are really concerned with "salvaging" your old analogue sets after the transition...

1) Any television with A/V inputs (yellow & red/white jacks, S-video connector, etc) can be hooked up to an ATSC tuner. The picture will not be much (any) better, but it will work.

2) Even if your TV lacks A/V inputs, it can be connected to a tuner box via an RF Modulater. This device converts A/V signals to channel 3/4 and plugs into the antennae jack. (~$30 at Radio Shack)

3) ATSC signals operate on the UHF frequencies and as such require a slightly modified antennae for best performance.

4) Being digital, ATSC signals tend to exhibit something called "cliff effect". Meaning when they come in, they tend to come in very well right up until the point where the built-in error correction can no longer compensate for bad reception. Then the reception falls off a cliff.

But the real question is do you really want to try and salvage your old set? Industry experts predict there will be a rash of cheap TVs (as well as expensive ones) made that recieve ATSC signals. The fact is the tuner chip sets are getting very cheap already and that trend will continue. And there are always companies willing to enter the market at the bottom price points.

Hope this helps,