Difference between Sync Gmail contacts on iPhone with iTunes and mail configuration using Microsoft exchange.

You can sync iPhone and Gmail contacts using iTunes and iPhone mail configuration using Microsoft exchange.

You can't sync contacts with direct Gmail configuration.

What is the difference between both of these?

If you configure it with itues, it copies gmail "My contacts" with custom labels and Images as well between your iPhone and gmail. It won't get copied to gmail mail contacts Immediately(assume your 3g/edge/gprs is enabled) when you create new contact on iPhone, but after the next sync with iTunes.

Using Microsoft change server contacts sync you can't get image and custom label. But it will immediately copied to gmail contacts.

Configured with gmail microsoft change server, disabled contacts sync, but you will get Global address list to search contacts.

To sync contacts

http://www.google.com/support/mobile/bin/answer.py?answer=138740&topic=14252

Configure using iTunes.

Click on configure to give google username/passwd.

The best way I follow is,

I sync it with iTunes to get copy images and custom labels, and configure gmail using microsoft exchange server, but disabled contacts sync to avoid duplicates. When you create new contact on iPhone, it get's copied to gmail when you sync it with Itunes.

And I can search contacts on gmail that are not existed on "my contacts group", because it's not synced to your iPhone.