Remact.Net is my current project. It uses WebSockets and Json for the remote actor messaging.
It has typesafety for C# actors but also supports dynamic types for browser based actors written in Java script.
My previous project was AsyncWcfLib. This is a C# library for actors communicating in a process or between different applications. The remote message passing uses WCF.
An actor catalog service enables actor discovery on several hosts.The hosts may run Windows or Linux.