How can I recursively delete folder with a specific name with PowerShell?

I tend to avoid the -Include parameter on Get-ChildItem as it is slower than -Filter. However in this instance (since it can't be expressed as a -Filter), this is what I would use:

Get-ChildItem . -Include .svn,_svn -Recurse -Force | Remove-Item -Recurse -Force

or if typing this at the prompt:

ls . -inc .svn,_svn -r -fo | ri -r -fo

This one should do it:

get-childitem -Include .svn -Recurse -force | Remove-Item -Force -Recurse

Other version:

$fso = New-Object -com "Scripting.FileSystemObject"
$folder = $fso.GetFolder("C:\Test\")

foreach ($subfolder in $folder.SubFolders)
{
    If ($subfolder.Name -like "*.svn")
    {
        remove-item $subfolder.Path -Verbose
    }       
}

For fast deletion, use -Filter

To recursively delete a folder with a specific name -Filter is significantly faster than -Include.

So, for visibility, here is the faster version of @Keith's answer:

Fully typed-out:

Get-ChildItem -Filter .svn -Recurse -Force | Remove-Item -Recurse -Force

Short version:

ls . -filter .svn -r -fo | ri -r -fo