When your battery fails on your iPhone you either have to void your warranty and replace it yourself (assuming you have the technical knowledge) or have Apple replace the battery for you.
The European Union doesn't seem to like the idea of a non-removable batteries in mobile phones and is considering the creation of a requirement that all mobile phone's must have easily replaceable batteries. If passed through this directive could force Apple to make the iPhone battery more easily replaceable via a rear cover that slides off or a couple screws allowing access to the battery. The battery would also need some sort of connector to allow easy swapping instead of the current design that has the battery soldered in.