Microsoft has introduced a new feature in Exchange 2010, autodiscover for mobile devices.  The idea here is that a user will enter their email address and their password.  The mobile will then query a DNS server looking for autodiscover.domain.com and grab an xml file from the web server.  The xml file will then configure the device for the user!  This communication is over SSL so it is secure.  Talk about making the deployment of mobiles even easier!  Of course the mobile device needs to be able to support audodiscover.