Generally, 3rd party iPhone batteries add extra talk time and do little extra but the INCASE Power Slider does so much more. Not only does the case wrap the precious iPhone 3G in a protective sleeve, it also adds a mini-USB port for easy syncing and charging. Yeah, it adds some bulk but it also bumps the standby time up to 330 hours and talk time on a 3G network to 5 hours (10 hours on 2G). It is expected to launch this holiday season and will be available online and at Apple Stores for $99.