Intellisense is not installed by default in Visual Studio 2005, however can be easily installed. The SDK contains a schema (silverlight.xsd) which defines how Silverlight XAML files should be defined and what is valid, as remember XAML is just XML. All you have to do is simply place a copy of the xsd into your Schema folder, which by default is:
C:Program FilesMicrosoft Visual Studio 8XmlSchemas
Next time you open Visual Studio, you will have intellisense for your Silverlight XAML. Apart from x:Name which doesn’t appear to be liked…but that’s only a small point.