In addition to accessing Google Apps mail from the Gmail web interface, you can send and receive mail from your favorite desktop client. Depending on the client, you can use either the IMAP or POP mail protocol. If you’re switching to Google Apps from Microsoft Exchange or some other Outlook service, you can use Google Apps Sync. This is a plug-in for Outlook 2003, 2007, 2010 or 2013 that lets you use Outlook to manage your Google Apps mail, calendar and contacts—along with your Outlook notes, tasks and journal entries.