It is always a real hassle - for example, today I am migrating a customer from an old XP laptop, to a Win 7 laptop with Office 2007 (existing copy of theirs).
To go from Outlook Express to Outlook 2007, you need to manually copy the Outlook Express database files, and address book.
You then have to install Windows Live Mail on the new machine, and import all the data and adresses. After that, you have to export from Live Mail to Outlook. You then have to manually set up the account.
It is beyond my understanding why all Microsoft email programs don't have an 'export all emails, accounts and addresses' function, and the capability to convert from older versions' exported files into the new one. You can copy registry information straight across if you go from Outlook --> Outlook (as long as user account name is the same) and all the account data will be copied, but going from one program to the other is always a mission.
Does anyone use any of the commercial solutions? I have tried a few trials at one stage for testing purposes, and none of what I could find was very good.
I would more than happily pay for a solution that would make migration easy between all MS software.