Apple has made it very easy to sync your iPhone or iPad calendar with Microsoft Outlook, however if you are a business user and your Outlook connects to a Microsoft Exchange email server it can be difficult and up until recently impossible to reliably synchronize your iPad or iPhone calendar with your Outlook Exchange calendar without the fear of losing all of your music and photos or the bonds of old fashioned cables.
For most people, using Google's Calendar Sync for Windows has been the best way to synchronize your Microsoft Exchange calendar with your iPhone. However, due to a well known and well documented bug in Google Calendar Sync which results in many reoccurring calendar events to not be synchronized, Google Calendar Sync is not a good choice.
Apple's new iCloud service offers synchronizing of Exchange and Outlook calendars however it only runs on PC's with Windows Vista or Windows 7 - leaving many users who's business forces them to use Windows XP out in the cold.
There are still two options to synchronize your Microsoft Exchange calendar on Outlook with your iPhone (or iPad) and even co-exist Google Calendar or iCloud calendars by using iTunes.
To get started be sure you have the latest version of iTunes for Windows installed on your PC. You can download iTunes from apple.com/iTunes.
After iTunes has been installed, open it by clicking the iTunes icon and select EDIT, then Preferences. On the preferences screen click the "Devices" option. On the Devices screen, put a check-mark in the box that says "Prevent iPods, iPhones, and iPads from Syncing automatically" - This will help prevent iTunes on your PC (which if just installed will have no music or apps, etc) from accidentally erasing everything on your iPhone or iPad the first time you connect it. Then press OK.
Using a USB cable, connect your iPhone to your work computer. After a moment you should see your iPhone (or iPad) name listed on the left side of the iTunes window in the Devices section. Click on the name of your device and under the Summary tab click "sync only checked songs and videos". Click on the Info option (top of the window) and uncheck all boxes except the "Sync Calendars with" box and be sure that "Outlook" is selected. Be sure to review the other options (such as the contact sync option) as this may overwrite the existing contacts on your device. Likewise, check all the music, video, etc settings to ensure that syncing is not enabled on your work computer. Be sure to review all options carefully.
Save your settings, and then press the SYNC button. Your Outlook/Exchange calendar should begin to sync with your iPhone or iPad!
Note that your work/Exchange calendar will be listed as a separate calendar named "work" - and will remain separate from any other calendars you may have configured such as a Google or iCloud calendar. However by setting which calendars to view in your iPhone Calendar settings (select ALL), they will all appear on your iPhone or iPad as one integrated calendar.
After your initial setup and sync with the USB cable, you can then select the "Sync with this iPhone over Wi-Fi" and from that point forward you will be able to sync wirelessly via your local Wi-Fi network assuming that your work computer is configured to connect to your wireless network. Remember that you will have to manually select your device in the 'devices' section and press the SYNC button each time you want to update or synchronize your calendar. To skip this step, go back to Preferences and then Devices, and UNcheck the box that says "Prevent iPods, iPhones, and iPads from synching automatically".
You should now be able to sync your Microsoft Outlook Exchange calendar on your work computer and still be able to sync your music, photos, etc on your home Mac or PC.