you just have to install the Secure Certificate on a Domain name, after that, you can set up Secure pages : some thing like : [url]https://[/url] ..... etc ...
so, when you want to secure the username and password, you have to secure the followin URL's:
1- secure the URL of the page contains the form of information (username and password) because it'll have the info, and post them
2- secure the handler, which means the page which form posts data into ... because it'll also have the information ...
while using the SSL is securing (encrp.) your data, so it is secured ...
now, how to install SSL is some thing else, and i think once you are doing a project for some one, have already the SSL, so just you have to ask them what they can encode for you, what pages, and you you do nothing more than using the (s) after http and nothing more in the coding ...
i have tried it this way and it works fine ..
hope this is helpful. ..