See here http://msdn.microsoft.com/en-us/library/office/ff865637.aspx
Sub CreateFromTemplate()
Dim MyItem As Outlook.MailItem
Set MyItem = Application.CreateItemFromTemplate("C:\statusrep.oft")
MyItem.Display
End Sub
Not just for .oft files
Set MyItem = Application.CreateItemFromTemplate("C:\temp\mail_item1.msg")
Edit – I keep forgetting about OpenSharedItem. http://msdn.microsoft.com/en-us/library/office/bb208171(v=office.12).aspx