Migration of accounts from Solaris to Linux

I am replacing a Solaris 2.6 server (Ultra 10) with a Dell PowerEdge 2800 
running RHEL ES 3.  The old server runs samba 2.2.5 and acts as a Windows 
NT PDC for our domain.  The users log in to their roaming profile form 
Windows XP computers which have joined the domain as machine clients.  The 
new server has its own host name but will replace the old server as PDC, 
authentication server and file server and the old server will be 
decommissioned.  The new server will run samba 3.0.9.

I plan to migrate the Unix and samba accounts from the old server to the 
new server and would like to preserve user and machine names as well as 
users' passwords in both Unix and samba if I can.

Has anyone successfully done what I want to do including preserving 
passwords?  If so, what method did you use?

Cheers,
Justin Sashiabel