Hello,
Actually I have a LAN with Windows 2000 Server and Active Directory domain,
I am planning to update the entire LAN to SBS 2003, and have some questions
about:
- Can I move the domain controller from the old server with Windows 2000
Server to the new with SBS2003?
- I don´t understand how exactly works the SBS licenses, there are "device"
and "user" licenses, wich is the real difference?
- If I have a littel more computers than licenses, example: 25 licenses and
26-27 computers, how this will work?

Thanks and greetings.

your question should move to microsoft.public.windows.server.sbs, the
SBS2003 group. This group is SBS4.x.

but meanwhile

Yes, this is often done as an upgrade of the current system. An alternative
would be a migration to new hardware. If you use google to search the
SBS2003 group you'll see lots of discussion.

A CAL is a label.
'user' CALs get stuck on the forehead of users, these users can use any
device to access the network.
'device' CALs get stuck on devices, users can access the network through
such a device without needing their own label.

see discussion of CALs