Migrating a FC5 server to Ubuntu

[A. Rick Anderson]

I am building a new Ubuntu machine.  Over the years, my FC5 machine has 
just become non-maintainable, so I'd like to migrate my existing user 
accounts, email etc from my FC5 machine to Ubuntu.  

My primary fat email client is Mozilla.  For some reason, on the FC5 
machinem, Thunderbird can't find the existing accounts, so it won't 
migrate them (part of why I want to just bag the old machine and start 
over).  I would like to figure out how to migrate these mail accounts to 
the new server.

The FC5 machine is a samba / PDC.  My ISP is HughesNet.

What is the best way to migrate these user accounts over?

I've got a High Point 133 FakeRaid card, and 2 250 GByte drives 
available, but based on what I am hearing, I don't see any point in 
using the High Point card, but should just use the software RAID in Ubuntu.