Delete wifi profiles in Windows

gistfile1.ps1

function PromptForRemoval {
    param (
        [string]
        [Parameter(Mandatory=$true)]
        $Networkname
    )

    $title = "Delete network $NetworkName"
    $message = "Do you want to delete the wifi network named $NetworkName"

    $yes = New-Object System.Management.Automation.Host.ChoiceDescription "&Yes", `
        "Delete network."

    $no = New-Object System.Management.Automation.Host.ChoiceDescription "&No", `
        "Keep network."
    $options = [System.Management.Automation.Host.ChoiceDescription[]]($yes, $no)

    $result = $host.ui.PromptForChoice($title, $message, $options, 1) 

    if ($result -eq 1) {
        return
    }

    netsh wlan delete profile name="$NetworkName"
}

$networks = netsh wlan show profiles | %{ $_.Split(':')[1] }

$networks = $networks | where { $_ -ne $null -and $_ -ne "" } | %{ $_.Trim() }

$networks | %{ PromptForRemoval -NetworkName $_ }

I recommend you replace $host.ui.PromptForChoice(...) with [CmdletBinding(SupportsShouldProcess)] and $PSCmdlet.ShouldProcess(...).
http://technet.microsoft.com/en-us/library/hh847781.aspx