Networked Component Interface For Free Unicies?

Graymalkin asks: "I'm in the process of learning COM for use with evil Windows apps and got to wondering what sort of competition for COM there is in the land of Open Source. I know about CORBA and its integration with both KDE and GNOME, but I want to know how far it extends? What's in the pipeline? Microsoft's .NET architecture ties together half a dozen technologies to make a pretty cool programming model. Is there anything comparable in Open Source land, not merely a object communication scheme (CORBA, COM) but a whole architecture based on distributed computing?"