Yes, you can have a multiline TextBox in Silverlight 2. Naturally you would look for the Multiline property, but it in Silverlight 2 it is AcceptsReturn. Here is an example:
<TextBox
VerticalScrollBarVisibility=”Visible”
HorizontalScrollBarVisibility=”Auto”
AcceptsReturn=”True”
BorderBrush=”Black”
BorderThickness=”2″
Margin=”5″>
</TextBox>