Thunderbird was suggested to me - it can (I think) pick up all of the old mail in Outlook Express (which will be a requirement) and it potentially has a much better spam filter. Can anybody confirm?
Sadly, it will most likely need to be a software/plugin solution - if I could get them using Gmail, I certainly would. I also know that I could have their accounts POP3'd into Gmail, allow it to do all the filtering, then POP3 what's left into their Outlook Express inbox... but I fear what will happen when they send an email and it goes through three stages... A software solution will just be easier for them.
So, Thunderbird users, how is it's spam-filtering skills?