While there are similarities between the digital TV systems chosen by other countries and the USA/ATSC system, there are marked differences, too.
To answer "hastalavista"s question, yes, there are systems of the kind you mention, but they are not called that.
Here's a brief rundown. More information can be gleaned from searches of the various HDTV fora on this site.
In Europe, there is no HD at all. The governments there decided to go for a 16:9 widescreen system based on PAL, known as 576i/50. This is SDTV. The transmission system is DVB-S (I don't think there's any FTA transmission of digital TV in Europe? Not sure.)
In Australia (where I live), SDTV has been specified as 576i/50(identical to Europe). EDTV (extended definition TV) is defined as 576p/50, while HDTV is defined as 720p/50 and 1080i/50. Note, 576p/50 is sometimes also manifested as 1152i/50. The transmission system is DVB-T (i.e. ota reception). The government has mandated 20 hours per week of native HDTV transmission (not upconverted) from each metropolitan ota station by 1993.
The 720p/50 and 1080i/50 systems can be thought of as "PAL-HD", even though the only relationship between PAL and these standards is the frame rate. The 576p/50 standard is essentially progressive PAL, although again the only similarity is the line count and the field rate since 576p is 16:9.
By comparison, the USA uses 480p/60, 720p/60, and 1080i/60. The resolutions are the same (except for 480p vs 576p) but the field rates are all 60 per second instead of 50 per second. Also, the USA appears to be the only nation in the world using the 8VSB transmission system. Everyone else is using CODFM, and experience appears to be showing that it's much cheaper to make a good CODFM (even mobile!) receiver than an 8VSB receiver. In regard of transmission system, nobody is following the USA and after hearing about the difficulties people have had receiving a signal it's easy to see why!
So in summary, resolutions are similar but that's about it.
- David Eddy