Export iPhone 3GS contacts into iCloud
Using an applitcation like iBackupBot found here:http://www.icopybot.com/itunes-backup-manager.htm

You can plug in your iphone 3gs and make a backup, it will back up all contacts Like so:


Now you go ahead and plug in your new iphone 6 and click the restore button.

Give it a minute or two, depending on your computer and you should have all your contacts on your brand new iPhone 6!

Hope you enjoy the iPhone 6, I know I am!