With the recent update of Windows Phone 7, AKA the "NoDo" update, Windows Phone got support for Copy/Paste. Any existing app out there instantly gets this support automatically, without the developer has to do anything.

However, copy/paste only works on TextBoxes, but what if you want to allow the user to copy text from a TextBlock? Today this is not possible. The trick to make this work is to simply use a readonly TextBox, and restyle it to look like a TextBlock. Here's the TextBox style that accomplishes this:

<Style x:Key="ReadOnlyTextBox" TargetType="TextBox">
	<Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}" />
	<Setter Property="IsReadOnly" Value="True" />
	<Setter Property="TextWrapping" Value="Wrap" />
	<Setter Property="Template">
		<Setter.Value>
			<ControlTemplate>
				<Grid>
					<ContentPresenter x:Name="ContentElement" />
				</Grid>
			</ControlTemplate>
		</Setter.Value>
	</Setter>
</Style>

Note: This approach actually also applies to "normal" browser-Silverlight as well.