How transfer Outlook Express data to Thunderbird - On Another Computer?

Within the next few weeks, as soon as I receive Windows 7, I am going to install a new SSD as a primary drive and perform a clean install. I already created a check list of everything I need to do so the process goes as smoothly as possible. However, there is one thing I need help with.

I use Outlook Express for email. Outlook Express is no longer available with W7 so I will move to Thunderbird. Thunderbird has an import function but I can see no obvious method of importing the data base of received/sent emails and the associated folder organization from Outlook Express unless it is installed on an accessible computer. Since this will be a clean install, I must be able to save all the old emails etc. to something that will be accessible from the W7 machine. How do I do this?

Outlook Express has been renamed Windows Live Mail, and is available for Windows 7. (MS is renaming a lot of their programs Windows Live XXX and providing them as a separate download to appease the monopoly witch hunters)

I would start looking there to see if there is a way to port the data from Outlook express to Windows Live Mail. It would probably be the easiest path since it is just moving up a version of the same product.

I haven't done it myself. There are some fairly detailed descriptions out there of how to upgrade from XP to Win7 and maintain your settings -- one of them might have a section about e-mail?