TextBlock has no Template property. As work around you can make a Button and customize it as TextBlock.
Here is an example:
<Button Content="Test"
Foreground="{StaticResource PhoneAccentBrush}">
<Button.Style>
<Style TargetType="Button">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid Background="Transparent">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Pressed">
<Storyboard>
<ObjectAnimationUsingKeyFrames
Storyboard.TargetProperty="Foreground"
Storyboard.TargetName="Txt">
<DiscreteObjectKeyFrame KeyTime="0"
Value="{StaticResource PhoneDisabledBrush}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<TextBlock x:Name="Txt"
Foreground="{TemplateBinding Foreground}"
Text="{TemplateBinding Content}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Button.Style>
</Button>