Thanks for the posting and the links. These seem to cover conversion from different address book/contact folders. This is not a problem as I use the ldif format - that works on all the main systems.
On Outlook Express (6) on Windows XP - if I click on the settings to import mail it just shows very old netscape mail options and some ms stuff. There is nothing for Thunderbird (which uses the mbox structure for email). Are the mail import options on Vista more modern and do they include the mbox option?