Now you can get access to lot of google products (like google voice, Picasa web album and more..) directly from Google apps account without signing into google account. In other word your google apps is your google account. Additionally you can sign in directly from any google sign-in page instead from your google apps sign-in page. According to Google: “Google Apps accounts are transitioning to a new infrastructure.”
Here is the complete list of services that are available and which are no available for your apps account.
Visit Here for official blog of google enterprise Post. Your Google Apps account is now your google account.
I think this feature is great and user-friendly.