Exchange doesn't pop up on new user creation to ask if you want to create a mailbox for the user.
we just upgraded from exchange 2003 to 2010. i was told that this type of integration is no longer available/supported but i do however remember while taking the class that it was available and working.
We're running 2007, and as far as I am aware, you're correct in that mailbox creation is not tied into ADU&C anymore. Can't say for 2010, but it is really a step backwards.
You can create the user account directly from Exchange management, however you can't choose the OU for account, which kinda defeats the purpose.
Correct, with Exchange 2007 and 2010 you can't create or manage mailboxes in ADUC. Do this in EMS, EMC or with a remote powershell session from the machine where you use ADUC.