Re #25: Depends on a lot of things... What language? ASP or PHP?  Is your site hosted on Linux or Windows?  Do you have multiple account to authenticate or just one username/password? Do you have a database or users or do you want to set the username and password to check for in the script itself?

Re #26: I assume the text of your site is in the HTML not in a database, therefore searching is more difficult. I would suggest to simply implement a Google search box for your site. All you need is copy-paste this script on your web page:  http://www.google.com/searchcode.html#both

Then it has to be either PHP or ASP. You don't want to do it in javascript and have the username and password written for anybody to just read it in the source.

Your whole site doesn't need to be PHP or ASP, just that one login page. If it's hosted on a Windows machine,then it probably supports ASP, while if it's hosted on Linux it probably supports PHP.  In either case, it's a very simple script.