I know that, in order to have Direct TV in the US, you have to have an unobstructed view to the south. That is because Direct Tv’s satellite is in geosynchronous orbit over Mexico (I believe).
Does that mean that if you live south of the satellite, you can subscribe so long as you have an unobstructed view to the north? Do international agreements allow (or prevent) this type of arrangement?
Geosynchronous orbits have to be over the equator. So they are not over Mexico.
You have to search the direct tv web site to find the page with the above quote.
I’m not sure about Mexico… DirecTV can’t legally offer service in Canada, though. Some people subscribe using US addresses, or they just decrypt the signal and watch it for free, which IIRC is legal in Canada.
If you have a US credit card with a US address linked to it, you can subscribe and then get a signal anywhere it’s available. DirecTV doesn’t encourage this (they say it’s prohibited), but then the don’t really know. One of the SDMB rules is we don’t promote breaking laws here in the USA. But… you’d probably be breaking a law in Mexico (or whereever), but that’s not explicitely prohibited by the rules. 
I’m assuming you’re asking because you’re an RV’er, and most of the available web resources are for RV’ers.
Do a web search for the DirecTV satellite positions. There are a lot of them that indicate where they are in the sky. RV’s use them, for example. Then all you have to do is point your dish that way.
I may have been hallucinating, but I’m pretty sure I recall seeing an advertisment for DirectTV on a sign in Peru last week. Given that parts of Miraflores seem like little chunks of the US transported into Lima, I’m not surprised that DirectTV might be available there.
In addition to an unobstructed to view to the transmitting satellite, the satellite must also be transmitting in your direction. Many satellites reduce their power requirements by using beampatterns to restrict their geographic area of coverage. In simple terms, they transmit like a flashlight rather than a bulb hanging from the ceiling.
I don’t know the specifics of DirectTV’s satellite.
DirecTV is available here in Panama.
Peru and Panama DirecTV are DirecTV Latin America, which is very widely available and probably very much advertised (in Mexico it is, anyway). I’m assuming that if the OP is looking for DirecTV, he really means US DirecTV, right?
Some of the sites indicate which of the DirecTV birds use spot beams versus whatever-you-call-non-spot-beams – dispersed radiation, maybe? Typically the local channels in each market are the ones on spot beams, since there’s no requirement for NBC Detroit to be beamed into Texas. This also allows the satellite to use the same channel (frequency, etc.) for multiple markets.
Lots of people pirate DirecTV in Canada. Technically it’s illegal, although personally I’ve never heard of anyone being charged.
Then you haven’t been listening very hard. Though it’s not usually the end users that get socked with fines, it’s the people who sell the end users the cracked cards to decrypt the signal.
I’m wondering how to get StarChoice in the US. I’m interested in it mainly for curling and news.
Well, any US-based satellite TV provider, really.
No, I’m not an RVer. But someday I may be an expat living in South America, Costa Rica perhaps. I’d hate to have to rely on local TV for my news, sports & entertainment.
I know several local Canadians who get Canadian satellite TV down here (USA). They have a Canadian address (a PO box is adequate) and credit card to pay for it. You will likely be able to do the same thing if you decide to move South.