The .NET Framework exposes a number of classes and methods in the System.Messagin g Namespace that allows access to MSMQ.
<edit>
Sorry, miss read your question....
The System.Messagin g namespace provides classes that allow you to connect to, monitor, and administer message queues on the network and send, receive, or peek messages.
I would assume from that statement that there is a way to connect to it on a network, but I'm not sure about a different Domain.</edit>
Comment