Yes, they have ignored the fact that the Snow Leopard Mail 'Wizard' helpfully sets you up for MobileMe as soon as it sees an @me.com address, because of course it's never heard of iCloud (and before anyone asks, no, there is no chance of Snow Leopard being updated to handle iCloud).
There is however a simple workaround which is detailed, with illustrations, in my page here:
Thanks for these instructions... They almost solved this issue for me. I combined your instructions with those from this Apple Discussion:
After using your instructions, here are the additional things that I had to do get outgoing mail working again:
1) From the "Accounts" pane of Mail's preferences, select "Edit SMTP Server List..." from the drop-down menu.
2) Under the "Account Information" tab, the Server Name should be "smtp.mail.me.com"
3) Under the "Advanced" tab, use your full email address for User Name (ie.g. email@example.com)
4) Ensure that the "Use Secure Sockets Layer (SSL)" checkbox is checked.
5) Click OK.
6) Close the preferences window. you should be good to go.
I hope that this helps some people; I know I was very frustrated when my Mail just quit working.
1st Gen. Intel MacBook Pro
MacOS 10.6.x Snow Leopard