Shawn has updates the Silverlight Control tutorial for Beta 2. Not only is this a good thing because of some of the changes in the Silverlight platform, but there was a big addition that greatly simplifies creating controls, Visual State Manager (VSM). This makes things a lot easier when you have to deal with a lot of states for an object (like a checkbox). Tim has some great samples of using this in Expression and how much easier it makes things. Shawn explains the update to the tutorial and gives an example of the dramatic code reduction the VSM gives on his post here.
For more of what has changed with Beta 2, check out the following information from Scott:
We have published a document that details the changes between Beta1 and Beta2 here that can help with this. I also recommend reading Shawn Wildermuth's What Changed in Silverlight 2 Beta2 and Upgrading your Silverlight 2 Projects to Beta2 posts for more details on some of the changes between Beta1 and Beta2.
Hope you find this information useful and can put it to good use. I am really excited that creating state for a control has been made much easier and it was not simple to do before. If you have tried to create a button with all the animation and states then you will know what I mean.