Have you ever heard of securit issues? Do not ever use SAMBA in a production enviornment. There are to many risks, and to many disadvantages to putting a SAMBA server in a production Internet enviornment. Without some serious firewall protection, your just asking for problems. Even with most patches installed on SAMBA, it is still inharrently inseccure.
If you want a script to write a file, then have that file transfered over to another location, I would use something like scp. its secure, its encrypted, and its fast. Plus, if your doing this on a regular basis, you can build a script and put it on the cron tab, and it will do it for you on a regular basis.
If the cron tab is not the way to go, I would next suggest just ftping it across. Make a folder on the webserver that is not viewable to the general public, make it writtable but not readable by a username that you create for the simple process of ftping something to your server. Then use something like proftpd to use as your ftp server, and set the home directory of that user that you created to the folder you made, and then tell proftpd to lock that user in that folder. That will make it so that if for some reason, a server got hacked, and a password got sniffed, that you could keep their mischief down to zero use.
If that sounds to complicated, you can always leave it on the server that it writes it on, and have php pull the file off itself. There are meany differant ways that you can do that. ftp, http, you pick... But what ever you do, do not use samba or nfs.