I'll start off by saying that I am a carphone warehouse employee and if that breaks the rules in any way then please expire this and accept my apologies.
The deal that is on at the moment (actually due to low stock levels on the 16GB iPhone) is that any iPhone 32GB taken on contract on the Orange network is only £20 more than the smaller 16GB version.
For example on a £35 a month 24 month contract the 16GB is £89 and the 32GB was £179 but for this weekend until the end of sunday the 32GB will be £109, a saving of £70. For orange contracts where the 16GB would be free, the 32GB will just be £20.
Not sure how hot this will get as it's one of my first posts and iPhone deals are quite often slated!