creating a list of people's emails

[rupertbj]

i have created a site (www.rupertbj.co.uk) which asks users to register with their e-mail address. I want to create a list of these saved into a file (mailinglist.txt) which i can then use to send e-mails out to those registered. My problem is that users should register or login using their e-mail address every time they access the site. How do i filter those already registered (and therefore stored in mailinglist.txt) so i don't get duplicates etc?
All help greatfully appreciated.
Rupert

[Anon]

on your form processing page you need to compare the enetered email address against your list to see if it's already there.

<?
$mailinglist = file ('mailinglist.txt');

if (in_array ($email, $mailinglist))
{
echo "$email is already in our records";
}

else
{
// code to enter email into txt file
}
?>

[Anon]

You really should use a real database for this instead of a text file. It would make your life a lot easier.