Google Apps of course is awesome email, docs, calender and such for organizations or individuals.
To further take advantage of Google Apps for your organization, it is possible to input additional DNS records.
In doing this, mail.yourdomain.com goes to your google apps mail, as well as others:
calendar.yourdomain.com – your google apps calendar
docs.yourdomain.com – your google apps docs
As Google continues to further add services to Google Apps, you may want to make additional CNAME entries for things such as reader, sites, and such.
Here are example DNS records for Google Apps:
@ 10800 IN A my.server.ip.address * 10800 IN A my.server.ip.address www 28800 IN CNAME yourdomain.com. mail 28800 IN CNAME ghs.google.com. docs 28800 IN CNAME ghs.google.com. calendar 28800 IN CNAME ghs.google.com. sites 28800 IN CNAME ghs.google.com. @ 28800 IN MX 10 aspmx.l.google.com. @ 28800 IN MX 20 alt1.aspmx.l.google.com. @ 28800 IN MX 20 alt2.aspmx.l.google.com. @ 28800 IN MX 30 aspmx2.googlemail.com. @ 28800 IN MX 30 aspmx3.googlemail.com. @ 28800 IN MX 30 aspmx4.googlemail.com. @ 28800 IN MX 30 aspmx5.googlemail.com.
Additional info from Google on Google Apps and DNS: