Many times auto-forwarding your email from our mail server to external email service providers is not wise choice,because the final receiveing end would often consider these as spam and the emails gets lost if the final destination rejects the emails.
An althernative would be to set up a POP3 retrieval from the external email service provider.This serves the same purpose as setting up email forwarding from your hosting account. By setting up POP3 retrieval, your mailbox at other email server connects to hosting mail server once a few minute, if new mail is found it's pulled to your mailbox at the external provider. This is far less abusive to the external service provider, hence,increasing your delivery rate.
To set up POP3 retrieval from Hotmail/MSN/AOL/Yahoo/Gmail please go to your Hotmail/MSN/AOL/Yahoo/Gmail email account help center and search for "Add an POP3 account"