IEを使ってみる
PS C:\Documents and Settings\k-oota> $ie = New-Object -ComObject InternetExplorer.Application
PS C:\Documents and Settings\k-oota> $ie.Visible = $true
PS C:\Documents and Settings\k-oota> $ie.Navigate("http://www.google.co.jp")
PS C:\Documents and Settings\k-oota> $ie.Document.InnerHTML = "<html><body><h1>Hello world</h1></body></html>"
+ $ie.Document.I <<<< nnerHTML = "<html><body><h1>Hello world</h1></body></html>"
PS C:\Documents and Settings\k-oota> $ie.Document.Body.InnerHTML = "<html><body><h1>Hello world</h1></body></html>"
PS C:\Documents and Settings\k-oota>