Archiving mail from an old Mac

Hi,

My father died recently and I now have his old iMac (15" 800Mhz G4). It's running an ancient version of OS X. I'd like to preserve the data on it for posterity. This mostly involves word docs and photos in iPhoto. These will be fairly easy to archive. However I'm wondering how best to archive the mail from his email account - it's currently stored in mail.app - however the mail account at his ISP no longer exists.

So, what is likely to be the best approach to capturing the email for posterity?

Best Regards,

John.

Thanks Brian.

In the end I had to copy the entire Home folder to a different Mac and then add the mailbox into mail.app