My scenario is I want to move mailboxes from Exchange 2007 to a new Exchange 2007 server within our domain.  I have 240 mailboxes to move and some of our users depend on OWA and Outlook Anywhere as well.  The mailboxes I will be moving are large in file size.  One mailbox alone is almost 8GB in data.  The challenge is to move the each user mailbox with no downtime whatsoever.   I already have planned this out by means of scheduling moving of mailboxes per batch or per department and on the OWA side, we will just have to allocate another public ip and point the Second Exchange Server box to that ip so that the users who are moved to the second exchange server will use the second OWA url while the others who are still on the primary exchange box use the existing OWA url.  Our network is just running in 10/100 which is why I am not sure as to how long would it take to move just a single 8GB of mailbox from one exchange to another exchange server.  The primary Exchange server is a Xeon cpu with 6GB of ram only.  I am hoping this server will not crash during mailbox move most especially the task might eat up a lot of system resource.  Aside from that, it is also running out of hard drive space as well.  The second Exchange server is actually the same brand and hardware but will have more ram 12GB to 24GB  and a couple of TB drives as well.  In addition, I am not sure if the steps below are exactly what I must do but I would appreciate if someone out there can provide me all the details I need.  Anyway, below are the steps I am thinking of.... - INSTALL SERVER 2003 on Second Server - Assign a unique COMPUTER NAME - Assign PROPER IP - INSTALL UPDATES - CONFIGURE DNS - JOIN SERVER TO THE DOMAIN - install pre-requistes - INSTALL EXCHANGE SERVER - Install Rollup and hotfixes - Copy all Organization Configuration and Server Configuration settings from Primary Exchange server to Second Exchange server (Mailbox, Client Access, Hub Transport, Accepted Domains, Send and Receive Connectors..etc) - Make sure all storage groups and databases on the Second Exchange Server are configured and mounted. - Perform a test maibox move from Primary Exch Server to Secondary Exch Server. - After mailbox move, on the users Outlook Client, go to Control Panel and change mail settings pointing to the Second Exch Server. - Open Outlook and test if all mails are intact. My next question would be how can I copy the Primary Exch Servers Distribution Group and Mail Contacts to the Secondary Exch Server?  Will there be any conflicts/problems on both Exchange servers having the same Distribution Group and Mail Contact content? Considering the amount of mailbox data I need to move, I will have to spend weeks/months just to be able to move everyone's mailbox.  This will probably have to be performed during weekends unfortunately.  I just want to make sure both Exchange Servers will work on the same domain until the time all mailboxes are moved.  I sure appreciate everyone's advice.  Thank you.

Software/Hardware used:
Windows 2003 Server and Exchange 2007