At times it may be difficult to remember the last names of acquaintances or business contacts when searching in your iPhone contacts; For these situations it is handy to sort the iPhone's default contact list by first name.
Follow these steps To Order iPhone Contacts By First Name:
Open the "Settings" application on your iPhone.
Locate and open the settings for "Mail, Contacts, Calendars"
Scroll until you find the "Contacts" section.
Select "Sort Order".
Change the sort order to "First, Last"
Check your "Contacts" application to ensure the new sorting has taken effect.