Does it cost money to upgrade?

I have the iPhone 4s and my upgrade is due and I was wondering does it cost money to upgrade to the iPhone 5 when it comes out

Nothing in this world is free. They might give you the upgrade at no cost but they'll insist you sign up for another long term contract.

No it's doesn't cost, you just ring up your network and tell them that your upgrade is due and they will do the rest

Yes. You have to pay for the phone. Should me around $200

Depends on your network, tariff and the deals available at the time. Unless you're on a quite high tariff it'll probably cost you something, on some networks you can't get a totally free iPhone unless you're paying about £60 a month.