The @icloud.com is an additional address on the same account, not a separate account, and your @me.com address will not be affected in any way. You need take no action to receive @icloud.com messages, they will deliver into your main inbox alongside the @me.com messages.
New to the forum, as I haven't encountered any bad experiences... but my @me (formerly @mac) accounts are gone! My calander, contacts and email are all gone. My @me mail shows no connection (strange little symbol). This all occured 3 days ago when i upgraded to ios6/icloud sign in. Help! Thanks!