After switching from Blackberry to Iphone, I forgot to remove Pocket Mac from my Macbook. As a result, when I synced my calendar to my iPhone using Mobile Me, a second calendar was created on my I Phone. Even when I removed Pocket Mac from my Macbook, he calendar remained. I searched everywhere for instructions on deleting it, without success. Then I figured it out. So simple.
Open up iCal on your macbook. You will see a list of your calendars on the top left. Cntrl click the one you want to delete, then scroll down to the “delete” option and Viola – Gone! Now re-sync your iPhone with iTunes. The offending calendar is gone.
This should work with any extraneous calender you’ve accidentally created on your I Phone. Mine just happened to be my Pocket Mac calendar.
Here is how you can delete a calendar on iPhone 5:
http://apple-ipad-iphone-ipod.blogspot.com/2012/10/how-to-delete-calendar-on-iphone.html