The first step you must perform, is to check that your package conforms to the PEAR coding standards.. After that, you need to make sure the package is approved by the PEAR community (currently this means that you get five votes (+1s) as replies to your package submission mail).
After you have recivied the sufficient amount of votes and your package is standards-compliant, you should ask for a PEAR website account by using the form at http://pear.php.net/account-request.php. After the account has been created, you can proceed with the next step.