LCD or Plasma? If it's LCD, you might as well just purchase a new one, as the cost to fix the screen is almost as much as just buying a new set. If it's a Plasma TV, it can only be repaired if the gasses between the two layers of glass haven't escaped - also a pricey repair. My advice is to just scrap it and get a new one - TV's these days aren't built to last.
It's probably very expensive! What part is cracked?
Will be cheaper to buy a new one