mail question for php script

[cruz]

I am getting ready to install my php script, but am not sure what to enter in the mail.This is the part in question.

Emails sent from:  	 	Email address the news/emails are sent from. Don't leave this empty or no emails will be sent.
Contact email: 		The email address where suggestions/complaints/comments from site are sent to. It will not be disclosed to the members.
Admin password: 		The default admin password you will use to login to the admin panel.
Admin password again: 		Retype the admin password.

I setup a email account on the site I am installing already. for email sent from, do I use that email or do I use a external email account? or do I use my out mail (smtp.sbcglobal.yahoo.com) for my sbcglobal account? If I use a external mail will the be able to see that from within the script? Thanks