Distributed cache component/service for C#?

Question

I'm a relative C# newbie, and as most of my recent experience has been in the J2EE realm I'm hoping somebody can help with some info on what's available in the C# world to support enterprise level distributed caching.
For a Silverlight/C#/SQL Server application I'm helping with it has some performance problems when its tries to scale.  My initial view suggests that the architecture would benefit from the use of a synchronized distributed cache. Are there any services/products available in the C# stack for this type of facility?