Like I always said: Google is great.  Follow Google, you can save some money and become knoweledgeable. Here I would like to introduce you the way how to free host your mail service of your domain by google.

1. Go to  Google APPS , then choose “begin free trial” (also google provide Premier Edition£33 / user account / year).

2. To sign up for Google Apps, enter your organization’s domain name.

3. After that,Google needs to validate you really own this domain. Google will ask you upload one special txt file to your hosting space.

4. Go to the control panel of your website, and change the MX RECORDS TO  ASPMX.L.GOOGLE.COM
Keep in mind that changes to MX records may take up to 48 hours to take effect(normally 24 hours enough).

***: As fas as I know,if your web hosting is in China, google apps doesn’t support.