Gmail

To set up :

1. Click the gear icon at the top of any Gmail page, choose Mail settings and open the Accounts and Import tab. (For Google Apps domains, open the Accounts tab.)
2. In the Check mail using POP3 section, click Add POP3 email account.
3. Enter the full email address of the account you'd like to access ie. Name@your_company.com, then click Next Step.
4. Gmail will populate sample settings, but we recommend checking with your other provider to learn the correct server name and port. Enter your Password.
5. Decide whether to:

        Leave a copy of retrieved messages on the server      

            If you'd like to keep a copy of each message Gmail retrieves in your other mail accounts, select
            the Leave a copy of retrieved messages on the server checkbox. This way, you can access
            mail in your other accounts, and in Gmail.

            Please note that some email services may still delete your messages when Gmail fetches them. If
            this option is checked, Gmail will instruct the other domain to leave the messages in place, though
            the final behavior is up to the other domain.

            If you'd rather delete copies of messages that Gmail retrieves, leave this option unchecked. Gmail
            will delete the messages from the other account as those messages are retrieved, meaning you'll
            only be able to read them in Gmail.

        Always use a secure connection (SSL) when retrieving mail

            If the email account being retrieved from supports Secure Sockets Layer (SSL) encryption, you
            can select this option to have all information sent through a secured connection.

            If you select this option, and your email provider doesn't support it, Gmail will let you know that
            your configuration failed. Clicking Show error details will likely reveal a Protocol error in this
            case. You'll need to uncheck this selection before continuing.

        Label incoming messages

            If you'd like to automatically label all messages that are retrieved from your non-Google account,
            select this option. You can choose to use the predefined label (your email address), or you can
            select an existing label or create a new one from the drop-down list.

        Archive incoming messages

            Mail from this account can be archived directly, without showing up in your inbox. Learn more about archiving.
    
6. Click Add Account.
7. Once your account has been added successfully, you'll have the option of setting it as a custom From address. This allows you to compose messages in Gmail, but have them appear to be sent from your other email account. Click Yes to set up a custom From address.