On February 17th, 2009, every portable television will no longer be able to receive over-the-air broadcasts. If you don't know why, see www.dtv.gov

If you have one of these portable televisions, and intend for it to be an "emergency" television, you'll be out of luck on February 18th.

If you want a portable ATSC (Digital) Television, there are TWO models on the market:
7" Screen - $199

5" Screen - $149

As far as I can tell there's no ATSC tuner box that's battery-powered.

One alternative, and it's not a great one, is to get a "tuner-on-a-stick" for a laptop computer.

Hey, thanks! I've been interested in seeing what kinds of portable digital TVs are available.

If you have an analogue portable TV which has a composite and audio inputs there is the Shinco DVB-100T portable digital TV adapter. It is slightly larger than the DVB-T USB sticks for Laptop computers but might be a useful adition when the analogue broadcast signal is turned off as it will allow you to view digital TV on older but still useful analogue portable TVs.

Yeah I hope they come up with something that can be ran on regular batterys cause it's kinda hard to charge stuff up when the lights go out. My little sony runs off of 4 C's and the cheapies run off 8 D's both are cheap when they are on sale at walgreens. But you would have to keep that one constantly charged to be usefull when it all hits the fan.

That unit will only work in the UK. It will not work in the US frequencies.

Is there a way to tell if my big screen will handle digital without the converter?

Someone in the marketing department of Insignia Products needs to learn how to convey specifications of their products. I laughed a bit at the 5-inch model that states, "Note: Digital content, regardless of broadcast resolution, will be displayed at standard-definition (480i) screen resolution," then states 324×234 as the pixel size of the screen.

What really made me scratch my head was the 7-inch model, which carries the same 480i resolution note, then states the pixel size as 234×480! It took me several hours of asking myself, "Are you supposed to turn it sideways or something," before I realized what they did. Someone really needs to learn that you measure the horizontal units before the vertical units, as in a "16:9" aspect ratio.

Still, it is nice to see some portable ATSC TVs coming out... even if you might need to stand still to get a signal. (ATSC broadcast formats have some mobility issues, last I knew.)

Perhaps that should have been 'works in most parts of the rest of the world except North America'. Yep you're right though the unit won't work in the US.

I've done a little bit of internet 'googling' on the subject. Wow the analogue signal is going to be turned of on February 17th, 2009 and on that day tens of millions of Americans will wake up that morning and won't be able to watch their televisions. Could this potentially become a TEOTWAWKI day

I've been surprised at the lack of ATSC to NTSC analogue coverter boxes available on the market for all the millions of perfectly servicable analogue NTSC sets that will still be operational.
In the UK the PAL analogue signal is also going to be turned of for the digital DVB-T signal in the next few years also but DVB-T set top convertion boxes have been available for about 5 years now. A DVB-T set top box can be purchased for around $30-40.
From what I've also gathered, there appears to be a problem with the quality of antenna required for the ATSC signal. So for many a new antenna installation and a new (expensive) High Def TV (Plasma or LCD panel) will be required once the NTSC analogue signal is turned off as millions of perfectly good CRT TVs make there way to the landfill.

As for the battery portable ATSC compatible digital TVs it will also have some problems as I've also read that the ATSC signal requires the TV to be stationary and cannot really be used wilst moving due to reception problems.

If you have a laptop you might consider something like the:
"Pinnacle PCTV HD Pro Stick- HI-DEF TV Tuner"

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2485646&CatId=1427
(I've never done business with these people but they have nice pictures on their web page)

Don't know how good they are..

Type the model # of your TV into Google and you should see the specifications. What you're looking for is an ATSC tuner. If your TV currently gets Hi-Def with an antenna, it's got an ATSC tuner in it.