E-mail-Forwards in Plesk
From Lunarpages Web Hosting Wiki
E-mail forwards (also know as redirect) are handy when you need to have multiple e-mail addresses all sending to the same e-mail account. This allows you to have multiple e-mail addresses as far as what the public can see but you really only have to check one.
How to Setup E-mail Forwards in Plesk
First step you need to take is login to your Plesk control panel, and then click on the domain name that relates back to the e-mail address you wish to setup the forward for. Now click on the icon labeled "Mail".
Locate the e-mail account that you would like to forward. Next, click on the icon labeled "Redirect".
On the mail redirect screen, click on the check mark box next to "Redirect". Then, in the empty text box, enter the destination e-mail address. This will be where you wish to redirect your e-mail. Check that the address you have entered is correct, and then hit the "OK" button. To remove the redirect you can take the same steps again.
Please note: Forwarding e-mails to other hosts (especially free e-mail services) will increase the blacklisting risk for a server.