Seperating the digitizer from the screen is nearly impossible, and pairing it back up with new glass is truely impossible. You'll need to buy a new digitizer/screen/glass combo which is almost as much as the phone itself.
I'd just get a gently used one off eBay.
If you're planning to DIY I highly recommend going on YouTube and looking up "LE55ON5" channel. The host disassembles practically almost every phone to the bare casing and reassembles it successfully.
Okay so I got a replacement phone but now how do I copy all the info from one phone over to the other phone? I don't see anything in the zune software to copy the texts and contacts etc.
I believe that text messages don't sync into the phone, however a contact list does. List should automatically sync right into your phone. make sure that when you set your phone up, you used the same email account. If you want to double check if your contact list even exists under your email account go onto:
choose my phone from the pull down list and select contacts located at the bottom of the page.
There you can see all your contacts as well as link your other accounts such as google, facebook etc.
If your contacts exist, click on manage on top of the bar and choose restore deleted contacts.