How hard is it to replace an iPhone 4 Screen?

[Scorpia]

I have cracked my screen, and im wanting to replace it myself due to high costs from apple. Everything still works perfectly.
I'm wondering how hard it is to do so? and if there is a risk of completly braking the phone? Also does it matter if you buy the screen off ebay? will the colours still be as good etc?
Thanks

 

[-aggie-]

It’s not overly hard, if you follow one of the numerous tutorials out there and are careful, but yes, of course you risk totally breaking your iPhone. For one thing, you could rip out a ribbon and then you’re pretty much out an iPhone.