There are a few HD channels, some details here http://hihd.pts.org.tw/
As for the rest, I don't know.
I've got a question about HD. My TV is only about one year old, and is a low-end LCD model. The TV has ports for S-video, AV, YPbPr and HDMI. The digital signal converter box I bought (the only one on the market that I know of) has ports for AV and YPbPr, no HDMI (no S-video either, but that's OK since it sucks). The guy at RT-Mart, where I bought it, says connect the TV to the box using AV. I tried that first, OK but not great - I switched it to YPbBr and it was much better.
Now the question: Assuming that any station is actually broadcasting in HD, do I have the equipment for watching HD TV? My understanding is that YPbPr is very good, but it's still analog. Again, the TV has an HDMI port, but the converter box does not. Am I going to need another converter box, or am I good to go?