Google Apps, MX Record change, & discussion lists


I’ve been using dreamhost for our email for 3 years now. We have dozens of email accounts, announcement lists, and discussions lists. I would really like to switch my email over to Google apps.

In the wiki, it says that switching my MX records over the Google will not affect my announcement lists, but there is not mention about whether an MX record change would affect my discussion lists. I assumed that I would have to migrate over all of the email accounts to google.

Will I have to move the discussion lists over to google as well?

Is there a way to keep the discussion lists through mailman and still move our email over to google apps?

I’ve heard the best way to do the migration is to replicate all my accounts on google ahead of time and then when I switch over, POP from the new google account back to my dreamhost to download the files to the new gmail account before deleting the dreamhost account. Is there a different way I should be doing this?

Thanks in advance for your advice.