I have registered to these forums new specifically to answer this question. I have found a good way to deal with this issue and I have already replied to a couple of people who, like me, have limited data, want to save battery power, simply just want more control over their phone, or all of these reasons at once. I decided to put this info into its own thread, because I foresee this as being a major sticking point for a lot of people when it comes to the Captivate and 3g and cell data control. AT&T has, for one reason or another, elected to have the ability to turn 3g off, removed from the Captivate. I too have the 200MB plan, which is more than enough provided that the phone doesn't randomly send out signal over cellular data tranmission. Well, it seems to do this. I'm sure there is an app or two that are the culprit, but even with WiFi on and background data turned off, I tracked my data usages and saw that packets of data were being mysteriously sent out over 3g overnight while I was asleep. Within just a few days of having the Captivate, I had accumulated 20MB of data usage. At that rate, I would have burned up my limit nothing flat. I did find a solution to control this however. You do NOT have to root your phone or do any crazy modifications. You will need to get an app called JuiceDefender When you install the app, it may seem overly complicated and will appear not to work. The program does require some settings tweaks in order to work properly, so I will step you through how to set it up to block 3g\2g\Edge or any other cellular data transmission, as well as how to control it through a single click of a widget icon. Turn off WiFi and let JuiceDefender set itself up. It will need to use your 3g settings in order to figure out how to deal with them and it won't work with WiFi on After the initial setup is done, switch it over to advanced control mode. You will see a whole list of buttons down at the bottom, some lit and some not. Lit means enabled. Above that you will see a list of different statuses. These are just here to let you know what the program is set to control. We only care about 3g in this case, so just go ahead an turn EVERYTHING off, starting from the bottom up for now (if you try from the top down, it will disable some buttons, and we just want everything off right now, just to be safe), via the buttons at the bottom. Make sure they are all turned off, especially the "battery" one, because that will affect how the program deals with your phone when the battery goes below a certain level and can give you unpredictable results if you aren't familiar with how it works or what it is for. Make sure everything is turned off, especially the 'WiFi" button. Now, with everything off, all of the buttons underneath "Data - WiFi - Timeout" should be completely grayed out. Now, you can go ahead and turn on the Data button (the very first button on the top). All of the buttons below should pop back up and be accessible again. If you are following along, you may be starting to understand how this system works. It's confusing at first, but essentially, all of the buttons on the rows below the very top ones are modifiers. In this case, modifiers for the "Data" function. Get it? If not, don't worry. It isn't too important. Just look and make sure none of the other buttons are lit up again. You may have to turn some off again. Schedule and battery can be a little stubborn, but as long as they are off, you are all set up. At the very top of the screen, is a button that will either say, "Enabled" or "Disabled". If it says "Disabled", click it and wait for it to say "Enabled" If all went well, the list at the top will say "No Nothing" for most everything except for "Scedule" which should say, "Keep Data disabled". This is good. Go ahead and hit your home key and back out to your home page again. You are done configuring. If you use "Advanced Task Killer" or something similar, be sure to exclude JuiceDefender from being killed. It will run in your system tray. Now, I'm sure you want some easy way to control all of this. That's simple. JuiceDefender comes with two widgets. If you scroll down, the widget list and you are trying to add a widget, you will see "JuiceDefender". Skip this. It can work, but it's a lot of steps and forced you to actually go into the program and change the settings again. You don't want this. Instead, keep scrolling down until you see "Toggle mobile data", with the JuiceDefender icon. Ones it pops up, it should say "Off" in red letters. All you have to do is tap it. It will ask for confirmation, but if you want it to stop asking confirmation, just tell it not to ask again when the message pops up. You are now set. All you need to do from here on out is tap the button to toggle on or off whenever you see fit. When it says "On" in green, that means your 3g is active. This does not in any way affect your ability to use WiFi, so I personally just leave it "Off" until I know I have no access to WiFi and need to use the net for any reason. Hope that is helpful and good luck. SIDENOTE: If you try to send a photo or something like that to someone else via text message 9which turns it into MMS messages), data service is required to be on. I'm not entirely sure why, because MMS is supposed to be included in AT&T's text plan and my old phone (a Pantech Duo) did not have any data plan on it, nor did it require the use of 3g. Perhaps someone else has knows a reason for this, but if you plan to message a picture to anyone, you'll need to turn 3g back on temporarily, or else your picture will infinitely say "Sending" until you turn it on; WiFi does not make any difference for this. The same goes when receiving photos through text. It will stick on "Receiving" until you turn 3g on. Have fun with your, now much more controllable, Captivate! [EDIT - 8-15-10] - Title of thread changed to clarify that this allows the ability to enable\disable all cellular data, including 3g\2g\Edge\etc, not simply just 3g. Some changes were made to the body to reflect this clarification as well. Using the methods describe above do not interfere with WiFi, Bluetooth or any of the other data transmission services outside of cellular data.