This is so stupid that I cannot find it anywhere!
Until now I used texblock with few words of text, so I just declared it as a property in text="my_short_text". Now I have several lines of text that I find really weird to put in the xaml.. I've tried to create a new text.txt resource file and tried to bind to the texblock with Path or Source but it didn't work! Where I have to keep my resourcese?
I know this is a noob question but I'm pretty new with WP7 and C#!
The use of an application resource file is where you'd want to store strings, ints, etc...
For WP7, there is an article on MSDN: How to: Build a Localized Application for Windows Phone. Scroll down to the section titled Replacing hard-coded strings with strings in a resource file.
There are examples of using resources all through the MSDN article; even though it's for localization, you can use the same concepts.