Archiving IMAP email

[Andy]

Hi all

I have an email account that is accessible via IMAP and is due to be
"expired" in a couple of weeks. I would like to be able to download all
the email I have on the server and save it to my desktop so I can access
me old emails.

Anyone know a good way of doing this? (I'm using Ubuntu 6.06LTS currently)

I have looked at a couple of articles about doing this with Thunderbird
but my email ends up in mbox files and Thunderbird refuses to open them
again.

Thanks

Andy