I spent a while this morning becoming somewhat baffled at the apparent lack of simple-to-use Timing features in .NET 4 in Silverlight. All I wanted was a simple solution to call a certain method inside the current scope and thread ever few seconds. However, many of the timing solutions are designed to work in a multi-thread manner, which takes everything out of scope and does not permit the required access to resources that I had in the standard scope.
Long story short, you can make use of System.Windows.Threading.DispatcherTimer to solve this problem. Here are the code samples.