For those who do not have the chance to get their hands dirty on the hands-on-labs, I have written a lengthy tutorial on Silverlight and WCF Service. As an ASP.NET developer, I found most of the examples of Silverlight authentication uses https and/or requires certificates, and so I sought to find my own method of authentication. I wanted to find a solution just like forms authentication and perform my custom login validation. To this, I have eventually come out with two "unofficial" methods, one (really) via ASP.NET forms authentication and the other via WCF authentication. On the former, I also wrote about accessing application / session variables as well as appSettings from the web.Config.
Also, if you are looking to combine your WCF services into a single client, you can do so. Check out this simple recipe here.
I am sorry for not able to provide C# code for some of the examples. If you really do need, just reply or leave a comment.
I have created some video tutorials - a five part series "Working with Silverlight and WCF". This is my first attempt at doing video tutorials. You can view them here at http://communityclips.officelabs.com/User.aspx?cid=1082743839742964991.
In case you are wondering, I used CommunityClips to create my videos. It is a free tool from Microsoft Office labs. The Community Clips website also contains lots of video tutorials. Details can be found here: http://communityclips.officelabs.com/Default.aspx.