Accented characters in mail sent by PHP

[Transistor]

How can I make accented characters (áéñ...) appear correctly in a mail sent by PHP?
I have tried these headers:
Mime-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable
But strange characters appear where the accented characters should be.

I don't think it is the e-mail client, I recieve other people's mail with accented characters all right, and although I have tried to copy the headers recieved by these messages, I just can't get accented characters to show up.

[Steven_Smith]

Maybe try UTF-8

Steve

[Steven_Smith]

$headers .= "Content-type: text/plain; charset=ISO-8859-1\r\n";
$headers .= "Content-Transfer-Encoding: 7bit\r\n";


$headers .= "Content-type: text/plain; charset=UTF-8\r\n";
$headers .= "Content-Transfer-Encoding: 7bit\r\n";