You have to buy the .com domain from a separate company. Google has very clear instructions for setting up services such as e-mail with the domain service, and on Google's side as well. Once you forward your mail traffic to Google, you can change all your mail settings from the domain management page in Google Apps. This means that changes don't require hours for the DNS records to update, just set it up 1 time in the beginning, and your set! On the downside, make sure to consider the extra cost of a domain name when looking at your budget.
answered Jan 05 '12 at 00:35