The main purpose of Google APPS is the ability to host mail service outside of your main domain and get full functionality of gmail services, with great antispam filters.
To setup you need to:
♦ create Google APPS account on http://www.google.com/apps/intl/en/group/index.html with necessary domain (example: domain.com )
♦ create needed mailboxes there (example: sales@domain.com )
♦ create necessary DNS MX records for domain in VPS.NET dashboard:
remove any MX records that lead to your VPS
add following records MX records:
1, ASPMX.L.GOOGLE.COM
5 ALT1.ASPMX.L.GOOGLE.COM
5 ALT2.ASPMX.L.GOOGLE.COM
10 ASPMX2.GOOGLEMAIL.COM
10 ASPMX3.GOOGLEMAIL.COM
After DNS propagation is complete, the setup will be finished