How to back up individual exchange mailboxes

Hi,
I was wondering if it is possible to back up individaual mail boxes in Exchange 2003.
Unfortunately our budget does not extent to allowing us to buy third party software. So I was wondering if there is a way of manually backing up a mailbox.
I had hoped it would be possible to simply create a new storage group to move the mailbox, but we are using the Standard edition and that only allow for one storage group.
Is there of doing this?