AT&T and Apple have begun to rollout MMS service to U.S. iPhone 3G and iPhone 3GS users. The service requires a carrier settings update—listed in the Settings application as AT&T 5.5—which is available through the Update feature in iTunes. AT&T originally promised to have the service available by late summer, but later changed that date to today; it rolled out the feature to a small test group early last week, and is reportedly…
