6
Well,
First you have to go to some place like versign.com and purchase a SSL certificate. Once you've done that, they'll send you the certificate and the instructions that you need to install that servicate onto your Web Server. In my case, this mean installing the certificate into a specific folder and configuring Apache to use that certificate.
Then, you can tell XOOPS to use SSL for login authentication in Admin -> System Administration - Preferences -> **SSL Stuff**.
The "SSL Stuff" is:
"Use SSL for Login"
"SSL Post Variable Name"
"URL Where SSL Login Page is Located"
Once you've filled all this stuff in, then your users should see a secure page whenever they try to log in to your site.
Please remember, however, that the vast majority of this activity is with your web server environment and outside the scope of XOOPS itself.