2. Click on DNS Functions.
3. Click Edit DNS Zone.
4. In the box on the right, select the domain you want to edit, and then click Edit.
5. Delete the existing MX record entry.
6. In the first box, enter your domain name (e.g. example.com).
7. Don't change the second box.
8. Select MX from the drop-down menu.
9. In the box to the right of the drop-down menu, enter 10 as the priority value.
10. In the next box, enter enter ASPMX.L.GOOGLE.COM.
11. Repeat steps six through eight for the rest of the MX record entries listed below. Add new entries in the Add New Entries Below this Line section.
NOTE: Make sure each entry is entered exactly as it appears in the following table. Each record must have the trailing dot.
Priority Mail Server
10 - ASPMX.L.GOOGLE.COM.
20 - ALT1.ASPMX.L.GOOGLE.COM.
30 - ALT2.ASPMX.L.GOOGLE.COM.
40 - ASPMX2.GOOGLEMAIL.COM.
50 - ASPMX3.GOOGLEMAIL.COM.
Click save.
Congratulations! Your MX records are now configured to point to Google. Keep in mind that changes to MX records may take up to 48 hours to propagate throughout the Internet.
From: http://support.google.com/a/bin/answer.py?hl=en&answer=54718
Collapse this post
3. Click Edit DNS Zone.
4. In the box on the right, select the domain you want to edit, and then click Edit.
5. Delete the existing MX record entry.
6. In the first box, enter your domain name (e.g. example.com).
7. Don't change the second box.
8. Select MX from the drop-down menu.
9. In the box to the right of the drop-down menu, enter 10 as the priority value.
10. In the next box, enter enter ASPMX.L.GOOGLE.COM.
11. Repeat steps six through eight for the rest of the MX record entries listed below. Add new entries in the Add New Entries Below this Line section.
NOTE: Make sure each entry is entered exactly as it appears in the following table. Each record must have the trailing dot.
Priority Mail Server
10 - ASPMX.L.GOOGLE.COM.
20 - ALT1.ASPMX.L.GOOGLE.COM.
30 - ALT2.ASPMX.L.GOOGLE.COM.
40 - ASPMX2.GOOGLEMAIL.COM.
50 - ASPMX3.GOOGLEMAIL.COM.
Click save.
Congratulations! Your MX records are now configured to point to Google. Keep in mind that changes to MX records may take up to 48 hours to propagate throughout the Internet.
From: http://support.google.com/a/bin/answer.py?hl=en&answer=54718