Silverlight 3 does not have a control similar to link label. This post tells you how you can add a hyperlink or linklabel in Silverlight 3.
Expression Blend:
1. Create a Silverlight project.
2. Add a Text Block object. Change the text to suit your requirement, let’s say My Website.
3. Under Properties->Brush tab, change the color to R=0, G=0, B=204.
4. Under Properties->Text tab, click on the Underline button. This will add underline to the text.
5. Under Properties->Common Properties, change the Cursor to Hand. (Choose from the drop down list)
6. Under Events tab, double click on MouseLeftButtonUp to add a event handler. In the code-behind, you can open the desired website.
Modifying XAML:
1. Create a Silverlight project
2. In MainPage.xaml, add the following lines
<TextBlock Text="My Website" TextWrapping="Wrap" TextDecorations="Underline" Foreground="#FF0000CC" Cursor="Hand" MouseLeftButtonUp="TextBlock_MouseLeftButtonUp"/>
In the event handler, add the code to open your website.