Today, Google introduced a new way to sync Google Contacts with your iOS device running iOS 5.0 or later. Google Contacts now supports CalDAV, an open source card format for sharing address books and contacts. Here's how you can set up the sync between your iOS device and Google.
Step 1) On your iOS device, go to Settings > Mail, Contacts, Calendars > Add Account... > Other > Add CardDAV Account
Step 2) Enter in your information for your account. The server you should use is "google.com", your username is your entire email address including the @gmail.com part. Your password fills the password field, unless you use 2-step verification, in which case you must use an application specific password.
Step 3) Click Next and it should verify your information and set up CardDAV for you. There may not be a noticeable difference now, but there are many possibilities with using an open source protocol such as CardDAV.
If you have any questions, feel free to leave a comment below!