We are going to implement new AD domain structure for organization with several branches through the country. Most of the branches have standalone Active Directories, some - just workgroups. AD is on Windows 2003 and Windows 2008, user PCs run Windows XP and Windows 7, new AD will be on Windows 2008.
Could you recommend good tool for user migration?
As I understood, same migration can be implemented for Exchange servers/accounts. Most of the branches currently access headquarter's mail server (Exchange) overseas; one or two branches use local mail servers. Would be great to automate migration process and optimize traffic if possible. Mail client is MS Outlook 2007, server will be Exchange 2007. Please recommend migration tool for Exchange.
You'll want to use the ADMT (Active Directory Migration Tool) to migrate your AD structures if you are going from AD environments to AD environments. You don't specify what the source Exchange is (2003/ 2007/ 2010) so I can't say for sure what you can use to migrate your exchange mailboxes. However, you can use the integrated Exchange Management shell to migrate mailboxes across a forrest if your source is 2000 SP3 or later, 2003 SP1 or later, or 2007. See this Exchange Team Blog post for more information: Exchange 2007 Cross Org Mailbox Migration