I have a forest functional level and domain functional level of my domain 2008. I have exchane server 2003 ent edition at the moment. I would like to install on a brand new hadware exchange server 2010 ent edition. For few months I would like my existing exchange server 2003 to still handle all the mail, which roles I will not be installing on the new exchange server 2010 so that there is no interferrance between the two? and mail will still flow from exchange server 2003 while exchange 2010 is also on the domain. After few months which roles I will introduce so that I can move everything to the new exchange server 2010.
-Also I need to know which Role or feature in exchagne 2010 if enabled start sending and receiving mail?