I wanted to note down the poweshell commands I used to import mail from .PST files to Exchange 2010 mailboxes.

The .PST files themselves were generated by Exmerge from mail stored on Exchange 2003 servers. This was then required to be imported into respective Exchange 2010 mailboxes.

Below is ways I used to import all .PST data into its respective mailboxes, a specific OUs mailboxes, or for an individual users mailbox.

Import mail from .PST files for all mailboxes: 

Get-Mailbox | Import-Mailbox -PSTFolderPath C:\PSTFiles

Import mail from .PST files for all mailboxes in the Finance OU: 

Get-Mailbox -OrganizationalUnit “DOMAIN.LOCAL/FINANCE” | Import-Mailbox -PSTFolderPath C:\PSTFiles

Import mail from a .PST file for an individual mailbox: 

Get-Mailbox -Identity "Andy Barnes" | Import-Mailbox -PSTFolderPath C:\PSTFiles