Web Deploy can be used together with the Microsoft Web Farm Framework to enable automated deployment across a web-farm.  You can install and configure Web Deploy on a primary server in a Web Farm Framework cluster – and the secondary servers within the web farm cluster will then monitor and clone any applications you deploy with it.  This allows you to use the exact same steps as above to deploy sites and applications across any number of machines within a web farm in an automated way.

Read my previous blog post about the Microsoft Web Farm Framework to learn more about how to enable this.