Hi Matthew,
It absolutely can be replaced, don't worry. It's just a matter of money, and I think the estimate of $500 is far off the mark sadly. I think you'd be looking at more like $1000 for Apple to do it.
Is your MacBook Pro a Core Duo or a Core 2 Duo model? ifixit.com lists a replacement screen module for a Core Duo at US$799 , plus another $15 for tools (which you do need, unless you already have laptop servicing equipment). Have a look through
http://www.ifixit.com/Guide/85.7.0.html first, to see if you're up to it.
It won't take too long, just be careful and paitent, and keep track of where the screws go, and you'll be fine. However, you may technically void the warranty, but if you do a good enough job, and something other than the screen has problems, chances are they won't notice it has been changed.