It's kinda funny - but something as simple as the iOS status bar can be confusing as quantum mechanics. Holly wrote a blog post, and an interactive web-based simulator, that explains the various settings and configurations for the status bar. It is definitely recommended reading: PhoneGap Developer's Guide to the iOS Status Bar.

P.S. Yes, this is a super short blog post, but I like to share important blog posts like this for the members of my audience lucky enough to avoid Twitter. Trust me - stay away...