Not sure if this has been posted yet, and I don't know if this is one of those "duh" functions that everyone but me knew about, but here's a (hopefully) helpful tidbit. If you hold down the home button, a folder pops up containing all active applications. You can very easily switch back and forth between open apps this way. I have been using this function to switch between my calorie counter and weight watchers diary since neither have all the functionality I need at the moment. Hope that helps some folks.