PowerShell function to send an email message.

##############################################################################
##
## Send-MailMessage
##
## From Windows PowerShell Cookbook (O'Reilly)
## by Lee Holmes (http://www.leeholmes.com/guide)
##
## Illustrate the techniques used to send an email in PowerShell.
## In PowerShell version two, use the Send-MailMessage cmdlet.
##
## Example:
##
## PS > $body = @"
## >> Hi from another satisfied customer of The PowerShell Cookbook!
## >> "@
## >>
## PS > $to = "guide_feedback@leeholmes.com"
## PS > $subject = "Thanks for all of the scripts."
## PS > $mailHost = "mail.leeholmes.com"
## PS > Send-MailMessage $to $subject $body $mailHost
##
##############################################################################

param(
    ## The recipient of the mail message
    [string[]] $To = $(throw "Please specify the destination mail address"),

    ## The subjecty of the message
    [string] $Subject = "<No Subject>",

    ## The body of the message
    [string] $Body = $(throw "Please specify the message content"),

    ## The SMTP host that will transmit the message
    [string] $SmtpHost = $(throw "Please specify a mail server."),

    ## The sender of the message
    [string] $From = "$($env:UserName)@example.com",

    ## Any credentials to supply
    $Credential,

    ## Determine whether an SSL connection should be used
    [Switch] $UseSSL
)

## Create the mail message
$email = New-Object System.Net.Mail.MailMessage

## Populate its fields
foreach($mailTo in $to)
{
    $email.To.Add($mailTo)
}

$email.From = $from
$email.Subject = $subject
$email.Body = $body

## Send the mail
$client = New-Object System.Net.Mail.SmtpClient $smtpHost

if(-not $Credential)
{
    $client.UseDefaultCredentials = $true
}
else
{
    $actualCred = Get-Credential $Credential
    $networkCred = New-Object System.Net.NetworkCredential
    $networkCred.Username = $actualCred.Username

    $bstr = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($actualCred.Password)
    $password = [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($bstr)
    [System.Runtime.InteropServices.Marshal]::ZeroFreeBstr($bstr)

    $networkCred.Password = $password
    $client.Credentials = $networkCred
}

if($UseSSL)
{
    $client.EnableSSL = $true
}

$client.Send($email)