You can link them together by using the tiny chain link icron that is to the right of the contact name when you're viewing their details
I am having contact issues as well. coming from the pre, every contact matched up perfectly and automatically. on this phone, a few linked together, however those that didnt will NOT link together no matter how many times i press link and even restart and battery pull the phone. The google contact will not link with my facebook contacts so i have doubles of almost everyone. Anyone else experiencing this issue or know how to fix it?
If you had the Pre, all your contacts were already backed up in your Google account. Reset your phone to factory and start over. Don't import from the Pre and you'll be good to go.