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On the iPod Touch 4th Gen the LCD and the digitizer are fused together. Typically it is recommended to replace the whole assembly. The problem when trying to separate the two parts is that the glue is applied to the entire surface of the LCD. Depending on how badly shattered the digitizer is this may pose more or less of a problem.

Your best chance of success is to replace the whole assembly not just the digitizer.
 
Don't be fooled by the "do-it-yourself kits" that only provide the front glass replacement. Like said above. the LCD is practically part of the front front glass/digi and attempting to remove/swap it would most likely not end up in your favor.

There are many companies who will do this service for you for roughly $100 online.

Best of luck to you!
 
If you live near a major metropolitan area you can easily find a local service that does it, we have some out here (California) that do it for 60$. Keep searching online, you might find something.
 
Repair is around $55 if you are willing to ship it out. I have a small iDevice repair business in Ohio. You can purchase the full screen assembly for about $30 but you also need adhesive strips to attach the new glass.
 
Check on ebay for ipod service. Many reputable people fixing crack screens for $40. You mail it in they mail it back fixed.
 
I repair iDevices

Hello, I run a small business out of Iowa city IA repairing apple devices. Here is my website. (currently it does not look the greatest. In the process of re-doing it)

www.theappledude.com

Send me an email through my website.

Let me know what color it is as well.

Thank you,
Jason
 
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