go to www.mozilla.com
download thunderbird for pc. install it. import all the outlook express mailboxes into thunderbird.
do a search for .mbox on your pc. you'll find some which should be in your thunderbird directory. copy those files to your mac. when you're in mail, it'll have an option to import it and it can read those files.
it works. trust me. i did it. and it should retain all your info.