Over the air HD?

I've lived in two markets, one of which had HD channels closely assigned with its main over-the-air channel, eg, regular NBC on ch 2, and NBC-HD on 2.1. The other has it pretty much randomly scattered in the 100s. So NBC would be on something like 100.1. I can't be more specific to your market, but that should give you some idea of where to look. If that AntennaWeb doesn't have an HD lineup, a message board somewhere might have one. I'm not sure if your cable company would help since some of them aren't that enthusiastic about helping people get HD for free over the air.

Whoops, I think I jumped the gun there. Both of those cases were with a basic cable line attached. I had tried to see what I could get with nothing attached, and I don't think I got any HD channels. So I'm guessing you will indeed have to get an antenna, but I'll let others help out on that front.

There may also be a setting for SD/HD (or maybe it was analog/digital) over-the-air signals. i remember one of my co-workers complaining about that.

Try http://www.tvfool.com, which will allow you to enter your street address and give you a good idea of what signals you should be able to pick up at your location, which direction you need to point your antenna and what channels (or virtual channels) you can find where. In the D/FW area, for example, most of the digital TV (all HD programming is digital) comes in the UHF band (channels 14+) (except the local ABC affiliate, which is in the VHF band (2-13)).

Also note that the HD tuner in your TV is separate from the non-HD tuner, so you may need to select a different "input" to see those channels. On my TV, I have to hit the TV button on the remote twice to get to the HD channels. And, yes, you will need an antenna of some kind, but not necessarily a special HD antenna.

but not necessarily a special HD antenna Because there's no such thing. Like bizwank said, any antenna will do, so long as it's large/powerful enough and oriented properly. I have a different make and model of HDTV than you do, but mine has a quirk with OTA digital(HD) - it will only display channels it found during the "auto-scan" setup. For analog broadcasts, I can key in any channel I know exists, and get reception(the quality varies, of course). With digital channels, I can key in any channel I like, but only those found during the scan will even attempt to get reception. Other channels that I know exist just give me a "not exist" message. If there's a scan feature in your menus, you might try it.