Hi, welcome to the forums.
There are no HiDef DVD players available yet* , you may be confusing them with upscaling DVD players.
I suggest you have a read around this forum on upscaling players because they are sometimes not all they are cracked up to be.
Is your display a normal TV, if so what connections does it have. What player have you got at the moment?
*in terms of true Blu-ray and HD-DVD - please can someone resist the temptation to go off an a WMV-HD or whatever tangent.