The next topics you will probably want to look at in your Silverlight studies include the following:
Customization of Silverlight controls
Silverlight network communications
Microsoft has produced a very good Silverlight site that contains a huge number of examples and video tutorials: www.silverlight.net.
Josh Smith has an excellent WPF/Silverlight tutorial series: http://joshsmithonwpf.wordpress.com/a-guided-tour-of-wpf/.
The Silverlight toolkit contains a number of additional controls, such as docking and graphs, which look very promising: www.codeplex.com/Silverlight.
Apress has a couple of Silverlight books:
3.145.69.192