For the Americans looking to receive Mexican stations (assuming those will continue to broadcast in analog), the situation seems to be similar to that of viewers who watch LPTV (low power TV). The viewer with an analog TV set will need to buy a digital converter box that has "analog pass-through" capability, so that the box can convey the over-the-air analog signal to the set as well as converting incoming digital signals. See the FCC's consumer advisory on LPTV at
http://www.fcc.gov/cgb/consumerfacts/DTVandLPTV.html
For the Mexicans looking to receive American stations, they can presumably buy converters, but I'm pretty sure that people outside the U.S. won't be able to get coupons; NTIA seems to be controlling this pretty tightly on a two-to-a-household basis, so I suspect they're also limiting it to U.S. citizens. But I haven't yet seen that addressed specifically. If they also want to continue receiving Mexican analog stations, they would need to get the same kind of analog pass-through box described above.
- Frederick Ellrod III,
Miller & Van Eaton