Hi, I want to get an iPhone 4 (I'm not interested in the iPhone 5, it'll be too expensive to start with), however I have a contract with vodaphone in which I currently have a htc wildfire. I know that vodaphone won't let me upgrade or even pay for the phone outright at a reduced rate, so I wondered if anyone knew if there is a good way to go about trading in a htc wildfire and buying an iPhone 4? I don't mind paying outright for the phone I just figured trading in the htc might have some value?

Thanks for your help.