Below are the steps required to forward all email sent to a Google Apps (Gmail) account to a different email account.

To simplify the example, we'll use old@example.com as the email address you want to forward emails from, and new@example.com as the address you want to forward email into.

  1. Log into the old@example.com webmail at gmail.com.
  2. Click the Gear Icon on the right of the screen and then click on Settings.
  3. Go to the "Forwarding and POP/IMAP" tab.
  4. Click the "Add a forwarding address" button in the forwarding section, type in new@example.com, and click Next.
  5. A confirmation email will be sent to new@example.com.
  6. Log into the new@example.com email account.
  7. Open the confirmation email and click the long link to confirm you'll allow forwarding.
  8. Go back to your old@example.com webmail at gmail.com and open the "Forwarding and POP/IMAP" tab again under Settings.
  9. Check the radio button to forward a copy of all incoming email to your new email address and choose the delete option in the second dropdown. We choose the delete option if you never want to worry about this email account getting full and bouncing emails.
  10. Be sure and click save at the bottom of the screen.
  11. Now all email sent to the old@example.com email address will be automatically sent to new@example.com.

 You can read more about this on  Google's help site.