To add an email account to Gmail, it must support POP3.
- Login to Gmail
- Go to the "Settings" page
- Click on the "Accounts" tab
- Click on "Add another mail account"
- Enter you username and password for that service.
Gmail should automatically set the POP3 settings if the email service is popular. If it doesn't detect the settings, you must get these from your provider.
You can also send mail on Gmail so that it appears it is coming from another account.
- Go back to the "Accounts" tab on the settings page
- Next to "Send mail as", click on "Add another email address"
- Enter the name and email address
- Check your email from that account, and confirm the process.