Well if the digi is cracked as well then it will need to be replaced.
The actual process of replacing the LCD or Digi is not that hard really. Most people buy them both together so that you don't have to heat up the glue to pull the digi off the LCD. That's the hardest part of the process as it can be tricky. So if you buy them together then it's just a matter taking some screws out. I think there is some videos for the Esteem on Youtube somewhere.
As far as which ones to buy I dont know. I have not bought any so I cant say one way or another. I would do a google search and see what other people say about whichever ones you are looking at. Someone somewhere has bought one and has wrote about it online so you should be able to find some info somewhere on it.
Hope this helps. Good luck