ScottGu has the detail of (and a walkthrough for) the Web Farm Framework, which looks to make high-uptime application publishing, deployment and maintentance a snap.
Last month we released a beta of the Microsoft Web Farm Framework. The Microsoft Web Farm Framework is a free product we are shipping that enables you to easily provision and mange a farm of web servers. It enables you to automate the installation and configuration of platform components across the server farm, and enables you to automatically synchronize and deploy ASP.NET applications across them. It also supports integration with load balancers - and enables you to automate updates across your servers so that your site/application is never down or unavailable to customers (it can automatically pull servers one-at-a-time out of the load balancer rotation, update them, and then inject them back into rotation).
The Microsoft Web Farm Framework is a 1 MB download, and can be installed on IIS 7 and above. It is available for free. You can download the first preview of this beta here: x86 / x64.
I'll be checking it out (when I'm back from China).