In the past, the source code for the samples could only be found in the documentation. Now, however, you can view the source directly from the sample browser by clicking a new button in the header section.
When you click the button, a new browser window opens and displays the code.
The code shown is the same as in the documentation, but now you don't have to dig for it! (Okay, so the digging is not much of a chore in most cases, but some topics are quite long and use multiple samples, making it harder to match the sample to the source.)
Silverlight User Education