The Google Bee had earlier written about Google planning to allow Google Apps users access to extended Google services. An official Google Help page further explains what this integration would entail.
This is going to take some explaining
The simplest way to explain how this works is the way Google explains it "Your Google Apps Account is now a Google Account." Previously, users had a Google Apps Account (thebee@mydomain.com) which allowed them access to Google Apps services (Gmail, Calendar, Docs, Sites, Groups, and Video.) and may have had a personal Google account (thebee@gmail.com, thebee@yahoo.com or any other) which allowed them access to all Google services (Blogger, Orkut, Reader, Voice, Picasa etc). But now, you can simply use your Google Apps account (thebee@mydomain.com) to sign in and use any Google service – no need to have two separate accounts.
As earlier hoped, the change does not mean a one click migration of all your accounts into a single Google Apps account. However, the portability of data from Google services allows you to easily port data from other accounts to your Google Apps account.
The Conflict
This change however creates a conflicting situation. What about the users who used their Google Apps email (thebee@mydomain.com) to create a personal Google account? To resolve this conflict, Google will simply rename your personal account to thebee+personal@mydomain.com.
Not the cleanest solutions. But it has to work for now.
Gina Trapani's graphic explains it



[...] services. First, Google Apps users did not have access to all Google services, and the doors were rather belatedly opened; Google Voice is still not a part of Google Apps and so on. It has happened [...]