PowerShell: "Opscode has made it simple for users working in Chef on Windows with a Ruby recipe to seamlessly integrate a block of PowerShell script into the middle of the recipe. The recipe language is simple with few constructs, so users don't realize they're in Ruby until they do something outside the domain specific language (DSL). Users get the benefit of Chef's management and automation, plus the execution of the PowerShell script."
IIS: "The Chef client is able to install IIS and configure web applications."
SQL Server: "Chef manages installation, configuration and updates to the SQL Server."
Windows Services: "Chef provides the automation tools for service management across all machines. It also provides analysis across the entire fleet to determine which services are running."You should also check out the results of Opscode's first Cookbook Contest.