[Samba] Migration from NT

[Jim Potter]

Hi All,
   At present I am running a largeish (~450 stations) NT based network 
(with win2k/XP clients) in a school in the UK, and I am looking into the 
feasability of moving to samba 3+LDAP over the summer. Has anyone had 
much experience of this, and are there any major problems? My concerns 
are with the following:

- Seamless transition from NT to Samba without having to re-add user 
accounts, change passwords, re-add workstations to the domain etc. - I 
get the impression that there are scripts to do this automagically
- The possibility of setting up several domains based on different 
sections of the tree - for instance creating an admin domain that draws 
its users from the staff branch list, and a curriculum domain that draws 
its users from the 'everyone at the school' branch.
- adding MacOS X machines

I already run Linux to do everything except domain logins and printing - 
this is the next sensible step

any top tips/experiences on this matter would be gratefully recieved

cheers

Jim Potter