Depends how the site does userids/password.

If the login is done through a netscape-style userid/password popup then you can pass your userid & password by setting your credentials using the HTTP::Request authorization_basic method. The lwpcook documentation that comes with LWP has a good example.

If the login is done with a userid/password form and cookies, you can use the HTTP::Cookies to set up a cookiejar and then simulate your login. You set up a cookie-jar for an LWP::UserAgent as follows:

use HTTP::Cookies;
my $agent = new LWP::UserAgent;
my $co=new HTTP::Cookies(file=>'./stored.cookies',autosave=>1);
$agent->cookie_jar($co);
[download]

Then you would do one post to "simulate" a login and get the cookies set, then just retrieve the page using $agent and all the apropriate cookies set by the login steps should be passed. Depending on how the site was written, it may take some tweaking to get this working just right.

There are other ways that sites can use to do user/password login authentication, but they are almost never user. Those two above cover about %99 of all sites that do some sort of login.