If you are going to sync multiple phones to iTunes in the same user account, you want to be careful if you are going to sync contacts with Address Book (Windows Address Book/Contacts folder if you are using Windows) under the "Info" tab in iTunes . What can happen is the syncing process will take the contacts from both phones and then merge them together. This will cause both phones to have all of the contacts from each phone and it can be a hard thing to recover from when it happens. Best advice is to create two seperate user accounts on the computer and sync each phone to its own unique user account. This way you get a seperate Address Book (or Windows Address Book/Contacts folder in Windows) for each phone.
Hope this helps,
Yes but a better and cheaper route may be this. How to use multiple iPods, iPads, or iPhones with one computer If you have two accounts and use the same apps on both phones have to buy copies for each phone. By using different libraries the same software can be used on multiple devices. I have two iPads and 2 iPhones using the same account just different libraries for each. Steve