The follwing script generates e-mail statistics of your exchange environment looking like this:
(Download the script HERE!)

Generated on Server: MAILSERVER
Date: 17.01.2012
Sent mails: 532435
Size of sent mails: 4.419,24 MB
Size of biggest mail out: 21,74 MB
Average size out: 217,69 KB
Quantity incoming mails: 66496
Size of received mails : 4.609,09 MB
Size of biggest mail in: 22,52 MB
Average size in : 161,96 KB
Overall quantity : 43172
Overall size : 9.028,33 MB

You have to change the following parameters:

$SmtpClient.Host = “YOUR_HT_SERVER”
$mailmessage.from = “Exchange_2010_NoReply@YOURDOMAIN.COM”
$mailmessage.To.add(“RECIPIENT@YOURDOMAIN.COM”)
# $mailmessage.CC.add(“CC_RECIPIENT@YOURDOMAIN.COM”)
$mailmessage.Subject = “Exchange daily message Report

$Localhost = $env:COMPUTERNAME
#Load Exchange PS Snapin
If ((Get-PSSnapin | Where-Object {$_.Name -eq “Microsoft.Exchange.Management.PowerShell.E2010″} ).name -eq ‘Microsoft.Exchange.Management.PowerShell.E2010′)
{
Write-Host “Exchange Snapin is already loaded….”
}

else
{
Write-Host “Loading Exchange Snapin Please Wait….”; Add-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010
}
Write-Host “running…”

$hubs = Get-TransportServer

# Get the start date for the tracking log search
$Start = (Get-Date -Hour 00 -Minute 00 -Second 00).AddDays(-1)

# Get the end date for the tracking log search
$End = (Get-Date -Hour 23 -Minute 59 -Second 59).AddDays(-1)

$Datum = $Start.ToShortDateString()

$receive = $hubs | get-messagetrackinglog -Start $Start -End $End -EventID “RECEIVE” -ResultSize Unlimited | select Sender,RecipientCount,TotalBytes,Recipients
$send = $hubs | get-messagetrackinglog -Start $Start -End $End -EventID “SEND” -ResultSize Unlimited | select Sender,RecipientCount,TotalBytes
$mreceive = $receive | Measure-Object TotalBytes -maximum -minimum -average -sum
$msend = $send | Measure-Object TotalBytes -maximum -minimum -average -sum

$anzahl = $mreceive.count + $msend.count
$volumen = ($mreceive.sum + $msend.sum) / (1024 * 1024)

$volumen = “{0:N2}” -f $volumen + ” MB”

$msendmb = $msend.sum / (1024 * 1024)
$vsend = “{0:N2}” -f $msendmb + ” MB”
$bigsend = $msend.maximum / (1024 * 1024)
$avsend = $msend.average / 1024

$bigsendmb = “{0:N2}” -f $bigsend + ” MB”
$avsendkb = “{0:N2}” -f $avsend + ” KB”

$mreceivemb = $mreceive.sum / (1024 * 1024)
$vreceive = “{0:N2}” -f $mreceivemb + ” MB”
$bigreceive = $mreceive.maximum / (1024 * 1024)
$avreceive = $mreceive.average / 1024

$bigreceivemb = “{0:N2}” -f $bigreceive + ” MB”
$avreceivekb = “{0:N2}” -f $avreceive + ” KB”

#$senders = $send | Group-Object Sender | Sort-Object Count -Descending
#$topsender = $senders[0].Name
#$topsender += $senders[0].Count

#$receivers = $receive | Group-Object Recipients | Sort-Object Count -Descending
#$topreceiver = $receivers[0]
#$topreceiver

$computer = gc env:computername
$obj = new-object psObject

$obj |Add-Member -MemberType noteproperty -Name “Generated on server:” -Value $Computer
$obj |Add-Member -MemberType noteproperty -Name “Date :” -Value $Datum
$obj |Add-Member -MemberType noteproperty -Name “Sent mails :” -Value $msend.Count
$obj |Add-Member -MemberType noteproperty -Name “Size of sent mails:” -Value $vsend
$obj |Add-Member -MemberType noteproperty -Name “Size of biggest mail out:” -value $bigsendmb
$obj |Add-Member -MemberType noteproperty -Name “Average size out :” -value $avsendkb
$obj |Add-Member -MemberType noteproperty -Name “Quantity incoming mails :” -Value $mreceive.Count
$obj |Add-Member -MemberType noteproperty -Name “Size of received mails :” -Value $vreceive
$obj |Add-Member -MemberType noteproperty -Name “Size of biggest mail in :” -value $bigreceivemb
$obj |Add-Member -MemberType noteproperty -Name “Average size in :” -value $avreceivekb
$obj |Add-Member -MemberType noteproperty -Name “Overall quantity :” -Value $anzahl
$obj |Add-Member -MemberType noteproperty -Name “Overall size :” -Value $volumen

$out = $Datum + “;” + $msend.count + “;” + $vsend + “;” + $mreceive.count + “;” + $vreceive + “;” + $anzahl + “;” + $volumen
$out | out-file c:\daily.csv -append -encoding default

function sendmail($body)
{
$SmtpClient = new-object system.net.mail.smtpClient
$MailMessage = New-Object system.net.mail.mailmessage
$SmtpClient.Host = “YOUR_HT_SERVER”
$mailmessage.from = “Exchange_2010_NoReply@YOURDOMAIN.COM”
$mailmessage.To.add(“RECIPIENT@YOURDOMAIN.COM”)
# $mailmessage.CC.add(“CC_RECIPIENT@YOURDOMAIN.COM”)
$mailmessage.Subject = “Exchange daily message Report $Datum”
$MailMessage.IsBodyHtml = $false
$mailmessage.Body = $body

$smtpclient.Send($mailmessage)
}

$obj = $obj -replace(“@{“,”")
$obj = $obj -replace(“=”,”:`t”)
$obj = $obj -replace(“; “,”`n”)
$obj = $obj -replace(“}”,”`n”)

sendmail $obj

Cheers,
Chris