According to the specs on the manufactures web page you should be able to use a tv as a monitor.
However, you may need to use a monitor so that you can adjust the monitor settings so that it will display in TV mode. From what I gathered, if your tv has a s-video or an DVI connection you should be able to do it. If not then you may need a s-video to rca or cable converter, and to be completely honest, my radeon has both these types of monitor outputs and I have used s-video to my tv and the picture really isn't that great, kind of fuzzy actually. I haven't tried the DVI connection, but one could possibly assume that since your card out puts in HDTV it may be clear enough to use as a monitor. But if that is the case wouldn't it be make more sense just to get a monitor instead of buying a hi-def tv, unless your filthy rich and your computer is for your Porsche.