You are asking several things here. You could just create an email link to
you for a password to your password protected areas of your site. You can
use a predesigned sign up form:
Create a pre-designed Web form
On the Objects toolbar, click Design Gallery Object .
Under Categories, click Reply Forms.
Under Reply Forms, choose a form.
Click Insert Object.
Double-click each control and select the options you want.
To read more about forms, go to Help and type in the word "forms".
As to the password protection, that is a server side function. Look to your
webhost for how to create a password protected folder. The information is
usually described in the FAQ section.
Then if you are going to use a form, read the article about HTTP uploading
protocol here:
http://msmvps.com/blogs/dbartosik/archive/category/1921.aspx
and the article: Publisher web publication forms 101 :
http://msmvps.com/blogs/dbartosik/archive/2006/01/07/80564.aspx
DavidF