Its pretty simple. All you need to do is change the template to make it look the way you want.
Here's a blog post which goes into the details for changing the template for a Button. All you need to do is change the template to something like:
<ControlTemplate TargetType="Button">
<TextBlock Foreground="Blue">
<ContentPresenter/>
</TextBlock>
</ControlTemplate>
Of course, you might be able to sneak out the template for a HyperlinkButton using Expression (it might also be lurking somewhere on MSDN) and reuse it...
With a button, I'd do the folowing (using codebehind blech):
<button Content="Navigate to my page!" Click="Button_Click" />
and in the codebehind:
void Button_Click(object sender, RoutedEventArgs e)
{
// Instantiate the page to navigate to
var page = new MyPage();
// Navigate to the page, using the NavigationService
// this assumes that the event handler is inside of a
// NavigationWindow
this.NavigationService.Navigate(page);
}