Google Apps is a professional version of the popular free email service Gmail. Gmail is a browser based email system, but some organizations want to benefit from Google Apps added level of security and still want to use the email interface their staff is familiar with like Microsoft Outlook. To accommodate the organizations Google provides 3 different ways in which you can have your email system working with MS Outlook.
Each style of connecting the two systems offers different benefits while each has unique drawbacks.
The POP3 email protocol is one of the simplest ways to setup your email in MS Outlook. POP3 settings push incoming emails to your MS Outlook inbox storing them on your local computer with the option of keeping a copy on the email server. POP3 settings can also be used to connect your email to your mobile devices, but with just simple email push capabilities it will not synchronize the emails you have read. For example if you read an email on your mobile device it will not be automatically marked as read in MS Outlook.
See Google POP3 Instructions.
IMAP email settings offer a more advanced synchronization of email and calendar information with both MS Outlook and on mobile devices. Using IMAP settings will automatically mark read emails across all your devices regardless of which device you read them on. IMAP connection will also enable you to synchronize calendar information to keep your MS Outlook and mobile devices showing the same appointments. Using IMAP settings does not keep your contacts and tasks synchronized and does not allow MS Outlook users to permanently delete emails that they have sent or received from the server.
Google Apps Sync
The most preferable method for connecting Gmail to MS Outlook is the downloadable application Google Sync which allows you to synchronize email, calendars, contacts and even tasks. Setting up Google Sync is easy to set up with MS Outlook and is also available to connect your iOS, Android, and Blackberry mobile devices.
The Google Sync software is usually the best option for connecting MS Outlook with Google Apps. Unlike the other available methods using the Google Sync tool allows the MS Outlook user to permanently delete emails. This Google Sync tool will also synchronize your contacts, and tasks keeping your MS Outlook profile fully updated.