I'm trying to develop my own app for windows phone 8, its an app to help visually impaired people text. I'm only starting off and im struggling to find stuff on how to create my own input method using a button so if the user taps or slides their finger on the screen it would print a letter into a text-box. Does anyone know if its even possible or any website to guide me in this task. thanks and any help would be much appreciated.
It is possible. Every UIElement has something like ManipulationStarted, ManipulationDelta and ManipulationCompleted events. You can play with them very well. Of course you need to program your own functions to recognize letters and so on.
You can read some information about that: http://msdn.microsoft.com/en-us/library/windowsphone/develop/ff426933(v=vs.105).aspx
I think you can find more articles if you search those events.