Look up your local area at the D* site to see if locals are carried.
However, if locals are carried in your area D* will beam them to you in SD. (except on special occasion CS and World S in Baseball this year was transmitted to some markets (mine! In glorious HD via D* for the duration.
To see your local broadcast channels in HD, you do need an HD STB with an OTA decoder. (I believe all current production models HD D* receivers include the OTA decoder, some of the early models did not).
You will need any signal locking old fashioned antenna on your roof/in attic etc. If you can tune your old analog broadcasts with an exsiting installed antenna, you will prob get most your digital OTA's just fine. You do not have to purchase an "HD rated" antenna. Just be able to lock in terristrial signals well using any antenna type rated for your area.
I also live in a condo, so if I plugged into the building's TV antenna (asumming we have) would I be ok??
As far as I am aware, yes that would work no problem. As long as your buildings antenna is tuned in decently and gets good reception, you should have no problem if there is a provided jack in the condos, or they allow you to run cable to it. The only issue you might have (antenna's always being being touchy) is regarding reception/pointing/multipath rejection etc, dependent upon how good an antenna the Condo installed, and how well they have it dialed in for reception?
When you purchase an HD D* receiver, there will be an ANT IN jack and the "Satelite in" jack. You plug your coxial for the OTA anntenna into your HD Reciever ANT IN, instead of directly into the back of your display. It will then decode any feeds when available in HD or send it on in SD if the broadcaster is currently broadcasting at lower resolution.
I currently do have access to East Coast feed of CBS, & NBC but not Fox (yet), in HD via the DirectTV feed. And am hoping for all HD (when available) sent via D* Sat feed, of my locals in the next year.
I will still always want an OTA decoder onboard any receiver I purchase, even when/if D* carries all locals HD. Since I lose my Satelite feed during storms. (here that can be for as long as an hour or two during bad ones) I will still always be able to tune in the locals via the OTA decoder/ and outdoor antenna.
Edit: on the channels you would receive. If D* currently provides your locals in your area via Satelite AND you are also using your onboard OTA/antenna feed decoder in the receiver you would get two sets of the same channels in your menu guide.
Currently for me it runs like this.
D* locals are mapped for 4 5 & 8 in channel guide. The OTA decoders aquires these same stations as 4.1 and 5.1 and 8.1 when the broadcaster is transmitting in HD I will will See it in HD only using these .1 channels. (some people just turn off the D* SD, 4 5 8 channels in their menu, when they have both.
This will change as D sends 4 5 and 8 here in HD themselves. Then if you wished you can skip ever installing OTA setup, yet still get HD. (again I will always run the OTA antenna in...due to rain fade).