Apple has posted an updated version of its iPhone User Guide (PDF Link) online. The new guide, which is labeled as “For iPhone OS 3.0 Software,” features several sections on iPhone 3G S-exclusive features, including entire chapters dedicated to the compass and Nike+ integration. Also mentioned in the guide are iPhone 3G S controls for the Apple Earphones with Remote and Mic, Voice Control, complete with instructions on how to use the feature,…