Question : Basic Exchange Mail Archiving

I am running MS Exchnage 2007 and need to come with a basic email archiving solution that can use the tools available. I was looking at using powershell to do this

Step 1.
Export mailfiles to PST via powershell for user accounts under a spefic OU and that have a warning limit on thier mailfile. Which I can successfully do with the following:
Get-Mailbox -OrganizationalUnit "domain/OU/Users" | Get-MailBoxStatistics | where {"IssueWarning" -contains $_.StorageLimitStatus} | Export-mailbox -PSTFolderPath "D:\EmailArchives\" -confirm:$false

Step 2:
I then need to delete all email items that are older than say 14 days from these affected mailfiles. I assume I would use the same "Get-Mailbox" but how do I specifiy the cmdlet to delete email items over a certain date, if this is at all possible?

Answer : Basic Exchange Mail Archiving

You can script this. To get the date of 2 weeks ago, you can start from here:
[DateTime]::Now.AddDays(-14)