PowerShell accessing a Exchange 2003 Mailbox

I'm still pretty new to PowerShell and was wondering if there is a way to control Exchange 2003 Mailboxes with PowerShell.

Specially what I am looking to do is set Out Of Office messages for different users when the request comes up.

I have been using Get-WmiObject to get information about Exchange servers, but really don't know where to go from here or if it's possible. 

I've seen in Exchange 2007 and later this becomes possible and looks easier with the additional modules available, but for now I'm stuck on 2003.

Thanks all!