Questions about OpenLDAP for account authentication

["Phill Edwards" <philledwards@gmail.com>]

I have a linux server which provides a number of services such as
samba, firewall, DNS, postfix, spam filtering etc to PCs on a small
LAN. The client PCs on the LAN are Windows XP. I find it a pain when
someone needs to change a password that you have to do it first on the
PC, then make sure it's the same on the corresponding linux account
and also for Samba. I thought I might use OpenLDAP so that there's
only 1 password to change and was hoping I could use it to manage
accounts. I've read a lot of HOWTOs but still have some questions.

- Can I use an OpenLDAP frontend (eg JXplorer) and OpenLDAP to create
new accounts on a linux machine, specify the group and have it create
a new home dir etc (like when you run useradd)?

- Does openldap replace the need to have the accounts in /etc/passwd?
Once I've copied the existing linux accounts from /etc/passwd, should
I delete them from /etc/passwd using userdel so that I don't have the
account in two places?

- I also want to use OpenLDAP to provide a common address book which
will be used mainly by Outlook. I know that Outlook can query the LDAP
address book, but can it also update it? It seems that there are lots
of apps to query OpenLDAP but updating the entries is a little arcane.

Regards,
Phill