If you don't remember or don't have your Postini password, you can reset using the Forgot Password feature on the Postini screen. Postini protects this link somewhat, so you'll need to be a little creative to see it.
To reset your password:
1) If you haven't already, stop by the Postini Message Center at login.postini.com (link will open in a new window).
2) For Log In Address, enter the e-mail address you'd like to reset the password on. For Password enter a few gibberish characters -- in order to see the Reset Password link, you have to enter something in the Password blank. Click the green Log In button.

3) You'll see the same login screen again, but with a link to reset your password . Click the Forgot Your Password? link (circled in red below). If you are not offered the option to reset your password, the e-mail account you're trying to use does not have active Postini service. Please contact client support for assistance.

4) Another screen will come up, saying:
A new temporary password will be sent to your email account when you click the Submit button
Click the Submit button. In a few minutes, you'll recieve an e-mail with a temporary password for Postini. Head back to the Postini Message Center at login.postini.com (link will open in a new window) and log in with your temporary password.