Applie is playing catch-up - Nexus S already has NFC built in. [techcrunch.com...]
the technology will allow you to use your phone in place of a credit card by simply tapping the phone against special sensors in retail stores. NFC will also allow for phones to swap data between each other with a minimal amount of hassle, as soon as developers add support for that (the Nexus S chip supports both read and write operations). This is basically future-proofing the phone, and a year from now I expect that most Android phones (and likely iPhones) will be shipping with NFC.