Usually, Icloud, MobileMe, and/or Calengoo (Google Calendars) are the main avenues which allow you to easily share calendars.
These were not ideal for me because ICloud did not sync my Microsoft Exchange Calendar/ and the other options required utilizing a calendar and more log-in info other than what is already used within our office.
My goal was to allow IPad users in my office to view eachother's Exchange Calendars.
-Each employee go to (Calendars in Exchange Outlook)
-Select the calendar to be shared
-Right Click the name of the calendar in the sidebar, then select (Share)
-Select Publish Online (Not to Webdav) If you need to set up a Windows Live account its very simple (this must be done in order to publish calendar)
-NOTE: you can set the calendar to ONLY allow invited users to view calendar OR make it open to all viewers (for me, making it open to all viewers was the only option that worked) Keep in mind that only those who have the link will be able to view the calendar anyway.
-Once the calendar is published you can send an invite
-Right Click the Calendar you published-Select (Share-Send invitation to published calendar)
-The recipient or the other coworker who receives the invite will be sent a URL to the calendar (Ending in .Ics)
-The recipient should open the e-mail using his/her IPad
-Click the link from Ipad and choose (Subscribe)
-The IPad should immediately add the Calendar to your ICal app.
(You can go to Settings to change the descriptions of each subscribed calendar. Change each calendar description to reflect the name of the coworker. You can switch from viewing each subscribed calendar by selecting the name or unselecting the name while viewing your calendar in ICal.
I hope this isnt too consfusing and provides some direction.