.NET Framework provides several good options for inter-process communication (IPC) like -
1. Web services
2. Remoting
3. Remoting with a TCP channel and binary formatter.
4. Named Pipes
...
Ref:
IPC in .NET - http://www.ddj.com/windows/184416711
Using IPC channels and .NET Framework 2.0 to communicate between processes -http://articles.techrepublic.com.com/5100-10878_11-6143016.html
Using Remoting IpcChannel in Framework 2.0 - http://weblogs.asp.net/israelio/archive/2005/01/04/346180.aspx
.NET Remoting Using a New IPC Channel - http://www.codeguru.com/csharp/csharp/cs_syntax/remoting/article.php/c9251
Using FileMapping on .NET as IPC - http://www.codeproject.com/KB/files/MemMap.aspx
.NET Remoting Using a New IPC Channel - http://www.codeguru.com/csharp/csharp/cs_syntax/remoting/article.php/c9251
Microsoft Community Blogs (Wonderful site) -http://www.microsoft.com/communities/blogs/PortalHome.mspx