ya, don't put it in the address bar
use sessions, cookies, and when you submit something using POST in a form the input names become variables,
Uname : <input type="text" name="uname">
Pword: <INPUT TYPE="password" name="pword">
when the user click the submit button $uname will hold the username and $pword will hold the password
when doing a login NEVER NEVER NEVER use the query string like that to auth the user. Best bet is to use sessions, cookies, or using a database to check it with perhaps a md5() check. ( if(md5($pword)) != md5($dbase_password))) { "Oops something went wrong"; }
Check out www.php.net for more info on that stuff or search www.hotscripts.com, www.zend.com for auth scripts and enjoy.
Jeremy
www.CodeHeadz.net