Microsoft has announced their Windows solution that’s similar to Linux multiseat: Windows Server Multipoint 2010. Architecturally, it’s actually similar to running several VNC clients in loopback mode on the same Linux server.
See Microsoft’s “Unlimited Potential” blog for more information from Microsoft.
“Unlimited” is over the top, but there’s certainly unfulfilled potential for multiseat (my talk on this), so raising awareness of the opportunity to lower the cost of computing this way is a good thing, whether you care about both Windows and Linux, or just one. Clusters of computing terminals that are cheaper to buy and much less expensive to maintain is a great thing for education and many other scenarios.
Let’s all make it happen.