syncing user passwd information between servers

[Noah]

Hi,

I am trying to figure out the Best admininstrative way to do the following:

We have two FreeBSD 6.2 servers and want to keep the passwd files in 
sync so all the same users can log into each machine, their UID's match, 
and when the update the password on one machine the other machine gets 
the password.  When we add the user to one machine then the other 
machine has an additional user too.

What is the best scheme that we can devise to get this working 
technically well?

Cheers,

Noah