In addition to your exchange account you can add a pop3 account to your outlook as well. I have several coworkers who do that. Go to tools, email accounts and choose "add a new mail account", select pop3 to add an external mail account. This has to be done through your outlook client; you cannot simply add an external address into AD to your account because exchange will only accept an "accepted domain" email address within your existing domain as an SMTP address for your exchange email account.

In addition to your exchange account you can add a pop3 account to your outlook as well. I have several coworkers who do that. Go to tools, email accounts and choose "add a new mail account", select pop3 to add an external mail account. This has to be done through your outlook client; you cannot simply add an external address into AD to your account because exchange will only accept an "accepted domain" email address within your existing domain as an SMTP address for your exchange email account.