I apologize to experienced users if this post seems redundant, but I hope it may be useful to my fellow newbies. I've noticed several here besides myself.
I like the Samsung Stratosphere, but as with most phones these days the documentation is scanty, meaning that there may be things you can do that you don't yet realize. I've found some interesting things by accident or playing around, by hunting for better documentation, and even by reading an article about another Samsung phone in a computer magazine.
For documentation, besides the little booklet that comes with the phone, there is a basic guide at http://support.verizonwireless.com/clc/devices/. If you are logged in, it will take you to an online guide for the device you own. On that page is a small link labeled "Device Manual" that will open a much more thorough PDF manual (direct link: http://cache.vzw.com/multimedia/mim/stratosphere/stratosphere.pdf). If you download this to the phone itself, you can read it with the QuickOffice app that comes with the phone (at least it came with mine).
One feature you may already have discovered is holding down on the Home key to view your six most recently used apps. That popup also has a button to access the Task Manager, from which you can exit from running apps (good to do if one of them is giving you problems) and tap on an app to see information about its functioning.
Some of the more interesting things I've learned have to do with swiping and pinching (using your fingers on the phone, not stealing! 
).
From your contacts list, you can swipe your finger across a contact left to right to start a phone call to that contact. Swiping your finger across a contact right to left creates a text message.
You probably already know that you have not just one but five Home screen panels, accessible by swiping left or right on the screen. Using a "pinch" gesture inward on the screen brings up a view of all five panels, from which you can go to another panel, set it as your main Home screen, etc. (This is the same view as Menu > Edit page.) Also, tapping the screen just below the notification bar at the top when you are on a Home screen briefly calls up a bar with a gear icon that gets you the same editing view, and five dots that you can tap to go from one panel to another.
Finally, on pictures in Gallery and on Web pages in the Browser, you can "pinch" outward to enlarge/zoom in and "pinch" inward to reduce/zoom out. I struggled to view a lot of Web pages (the double-tap on the screen only zooms in so far) before I stumbled across this gesture (which is sort of documented on p. 22 of the PDF manual, but not under the Browser discussion).
Perhaps other newbies would like to add their discoveries to the thread?
