Transferring contact list from Iphone 4 to a Windows 7 PC and vice versa I would like to transfer the contact list from my iPhone 4 to my Windows 7 PC.  How can I do that?  Which software should I need?

After I transfer all my contacts to the PC, I want it to copy back to another iPhone 4.
You can do it with iTunes! You can sync iPhone contacts with Windows address book, Yahoo! contacts, Google contacts or Outlook contacts... And after that you could sync it with another iPhone...
Also, you can use Apple's mobileMe service (which is NOT free). They have a sync tool for Windows (me.com)...