IIOP.Net is the best!
As wrote earlier, I searched for small library (or framework) for exposure remoting interface with C# and Java bindings...
Today i tested a library IIOP.NET. It is really working library, and maybe, the best library.
Heh... And again it's using basics from CORBA.
But have some restrictions:

• .NET Compact Framework does not supported (Not because the library does not support, and because of Microsoft which have not implementation .NET Remoting on CF).
  
• Have some problems with interoperability Java 2 C#
• Generic collections does not support (but i have added this support).

The test has following remote interface:

public interface ITest
{
string produceHello(string param); // simple operation
ITestRemoteObj getRemoteObj(); //remote reference
ITestValueType getObjByValue(); // object by value (valuetype)
ICollection getCollection(); // collection

// my support for generics
System.Collections.Generic.ICollection<ITestValueType> getGenericCollection();

// callback example
void doCallBack(ITestCallBack callBack);
}

It's is really worked for C#.. But with Java (over JavaIDL) have some troubles...
If you needs support for a "generic" collections for IIOP.NET, then welcome to sourceforge.
I have already submited the patch there.